Initialize *FLAGS variables with objects that can add flags either as strings or lists.

59 files changed, 340 insertions, 127 deletions

diff --git a/src/engine/SCons/Tool/386asm.py b/src/engine/SCons/Tool/386asm.py
index 7a18a40..bb8b780 100644
--- a/src/engine/SCons/Tool/386asm.py
+++ b/src/engine/SCons/Tool/386asm.py
@@ -34,15 +34,17 @@ selection method.
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
-import as
 from SCons.Tool.PharLapCommon import addPharLapPaths
+import SCons.Util
+
+import as
 
 def generate(env):
     """Add Builders and construction variables for ar to an Environment."""
     as.generate(env)
 
     env['AS']        = '386asm'
-    env['ASFLAGS']   = ''
+    env['ASFLAGS']   = SCons.Util.CLVar('')
     env['ASCOM']     = '$AS $ASFLAGS $SOURCES -o $TARGET'
     env['ASPPCOM']   = '$CC $ASFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS $SOURCES -o $TARGET'
 
diff --git a/src/engine/SCons/Tool/BitKeeper.py b/src/engine/SCons/Tool/BitKeeper.py
index 3208b67..2983c14 100644
--- a/src/engine/SCons/Tool/BitKeeper.py
+++ b/src/engine/SCons/Tool/BitKeeper.py
@@ -37,6 +37,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 import os.path
 
 import SCons.Builder
+import SCons.Util
 
 def generate(env):
     """Add a Builder factory function and construction variables for
@@ -50,7 +51,7 @@ def generate(env):
 
     env['BITKEEPER']         = 'bk'
     env['BITKEEPERGET']      = '$BITKEEPER get'
-    env['BITKEEPERGETFLAGS'] = ''
+    env['BITKEEPERGETFLAGS'] = SCons.Util.CLVar('')
     env['BITKEEPERCOM']      = '$BITKEEPERGET $BITKEEPERGETFLAGS $TARGET'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/CVS.py b/src/engine/SCons/Tool/CVS.py
index 6d5b046..20bbb6a 100644
--- a/src/engine/SCons/Tool/CVS.py
+++ b/src/engine/SCons/Tool/CVS.py
@@ -36,6 +36,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 import os.path
 
 import SCons.Builder
+import SCons.Util
 
 def generate(env):
     """Add a Builder factory function and construction variables for
@@ -57,8 +58,8 @@ def generate(env):
     setattr(env, 'CVS', CVSFactory)
 
     env['CVS']        = 'cvs'
-    env['CVSFLAGS']   = '-d $CVSREPOSITORY'
-    env['CVSCOFLAGS'] = ''
+    env['CVSFLAGS']   = SCons.Util.CLVar('-d $CVSREPOSITORY')
+    env['CVSCOFLAGS'] = SCons.Util.CLVar('')
     env['CVSCOM']     = '$CVS $CVSFLAGS co $CVSCOFLAGS ${TARGET.posix}'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/Perforce.py b/src/engine/SCons/Tool/Perforce.py
index 3526952..3813d99 100644
--- a/src/engine/SCons/Tool/Perforce.py
+++ b/src/engine/SCons/Tool/Perforce.py
@@ -36,8 +36,8 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 import os
 
 import SCons.Builder
-import SCons.Util
 import SCons.Node.FS
+import SCons.Util
 
 # This function should maybe be moved to SCons.Util?
 from SCons.Tool.PharLapCommon import addPathIfNotExists
@@ -58,7 +58,7 @@ def generate(env):
     setattr(env, 'Perforce', PerforceFactory)
 
     env['P4']      = 'p4'
-    env['P4FLAGS'] = ''
+    env['P4FLAGS'] = SCons.Util.CLVar('')
     env['P4COM']   = '$P4 $P4FLAGS sync $TARGET'
     try:
         environ = env['ENV']
diff --git a/src/engine/SCons/Tool/RCS.py b/src/engine/SCons/Tool/RCS.py
index 3b9547c..a8f9168 100644
--- a/src/engine/SCons/Tool/RCS.py
+++ b/src/engine/SCons/Tool/RCS.py
@@ -34,6 +34,7 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Builder
+import SCons.Util
 
 def generate(env):
     """Add a Builder factory function and construction variables for
@@ -47,7 +48,7 @@ def generate(env):
 
     env['RCS']          = 'rcs'
     env['RCS_CO']       = 'co'
-    env['RCS_COFLAGS']  = ''
+    env['RCS_COFLAGS']  = SCons.Util.CLVar('')
     env['RCS_COCOM']    = '$RCS_CO $RCS_COFLAGS $TARGET'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/SCCS.py b/src/engine/SCons/Tool/SCCS.py
index b75d676..8230241 100644
--- a/src/engine/SCons/Tool/SCCS.py
+++ b/src/engine/SCons/Tool/SCCS.py
@@ -34,6 +34,7 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Builder
+import SCons.Util
 
 def generate(env):
     """Add a Builder factory function and construction variables for
@@ -46,8 +47,8 @@ def generate(env):
     setattr(env, 'SCCS', SCCSFactory)
 
     env['SCCS']         = 'sccs'
-    env['SCCSFLAGS']    = ''
-    env['SCCSGETFLAGS'] = ''
+    env['SCCSFLAGS']    = SCons.Util.CLVar('')
+    env['SCCSGETFLAGS'] = SCons.Util.CLVar('')
     env['SCCSCOM']      = '$SCCS $SCCSFLAGS get $SCCSGETFLAGS $TARGET'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/Subversion.py b/src/engine/SCons/Tool/Subversion.py
index 92839bc..85e032b 100644
--- a/src/engine/SCons/Tool/Subversion.py
+++ b/src/engine/SCons/Tool/Subversion.py
@@ -36,6 +36,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 import os.path
 
 import SCons.Builder
+import SCons.Util
 
 def generate(env):
     """Add a Builder factory function and construction variables for
@@ -54,7 +55,7 @@ def generate(env):
     setattr(env, 'Subversion', SubversionFactory)
 
     env['SVN']      = 'svn'
-    env['SVNFLAGS'] = ''
+    env['SVNFLAGS'] = SCons.Util.CLVar('')
     env['SVNCOM']   = '$SVN $SVNFLAGS cat $SVNREPOSITORY/$SVNMODULE$TARGET > $TARGET'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/ToolTests.py b/src/engine/SCons/Tool/ToolTests.py
index cd809df..5ddac19 100644
--- a/src/engine/SCons/Tool/ToolTests.py
+++ b/src/engine/SCons/Tool/ToolTests.py
@@ -52,7 +52,7 @@ class ToolTestCase(unittest.TestCase):
         t = SCons.Tool.Tool('g++')
         t(env)
         assert (env['CXX'] == 'c++' or env['CXX'] == 'g++'), env['CXX']
-        assert env['CXXFLAGS'] == '$CCFLAGS', env['CXXFLAGS']
+        assert env['CXXFLAGS'] == ['$CCFLAGS'], env['CXXFLAGS']
         assert env['INCPREFIX'] == '-I', env['INCPREFIX']
         assert env['TOOLS'] == ['g++'], env['TOOLS']
 
diff --git a/src/engine/SCons/Tool/aixlink.py b/src/engine/SCons/Tool/aixlink.py
index d987016..2deb1f1 100644
--- a/src/engine/SCons/Tool/aixlink.py
+++ b/src/engine/SCons/Tool/aixlink.py
@@ -35,6 +35,8 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 import os
 import os.path
 
+import SCons.Util
+
 import aixcc
 import link
 
@@ -55,8 +57,8 @@ def generate(env):
     link.generate(env)
 
     env['SMARTLINKFLAGS'] = smart_linkflags
-    env['LINKFLAGS']      = '$SMARTLINKFLAGS'
-    env['SHLINKFLAGS']    = '$LINKFLAGS -qmkshrobj -qsuppress=1501-218'
+    env['LINKFLAGS']      = SCons.Util.CLVar('$SMARTLINKFLAGS')
+    env['SHLINKFLAGS']    = SCons.Util.CLVar('$LINKFLAGS -qmkshrobj -qsuppress=1501-218')
     env['SHLIBSUFFIX']    = '.a'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/ar.py b/src/engine/SCons/Tool/ar.py
index 653836f..0522adc 100644
--- a/src/engine/SCons/Tool/ar.py
+++ b/src/engine/SCons/Tool/ar.py
@@ -35,6 +35,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Defaults
 import SCons.Tool
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for ar to an Environment."""
@@ -46,9 +47,9 @@ def generate(env):
         arcom = arcom + '\n$RANLIB $RANLIBFLAGS $TARGET'
 
     env['AR']          = 'ar'
-    env['ARFLAGS']     = 'r'
+    env['ARFLAGS']     = SCons.Util.CLVar('r')
     env['RANLIB']      = ranlib
-    env['RANLIBFLAGS'] = ''
+    env['RANLIBFLAGS'] = SCons.Util.CLVar('')
     env['ARCOM']       = arcom
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/as.py b/src/engine/SCons/Tool/as.py
index 14a2d43..3d630e3 100644
--- a/src/engine/SCons/Tool/as.py
+++ b/src/engine/SCons/Tool/as.py
@@ -59,7 +59,7 @@ def generate(env):
         static_obj.add_action(suffix, SCons.Defaults.ASPPAction)
 
     env['AS']        = env.Detect(assemblers) or 'as'
-    env['ASFLAGS']   = ''
+    env['ASFLAGS']   = SCons.Util.CLVar('')
     env['ASCOM']     = '$AS $ASFLAGS -o $TARGET $SOURCES'
     env['ASPPCOM']   = '$CC $ASFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES'
 
diff --git a/src/engine/SCons/Tool/bcc32.py b/src/engine/SCons/Tool/bcc32.py
index 6f63525..6d3acca 100644
--- a/src/engine/SCons/Tool/bcc32.py
+++ b/src/engine/SCons/Tool/bcc32.py
@@ -59,10 +59,10 @@ def generate(env):
         static_obj.add_action(suffix, SCons.Defaults.CAction)
         shared_obj.add_action(suffix, SCons.Defaults.ShCAction)
     env['CC']        = 'bcc32'
-    env['CCFLAGS']   = ''
+    env['CCFLAGS']   = SCons.Util.CLVar('')
     env['CCCOM']     = '$CC -q $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES'
     env['SHCC']      = '$CC'
-    env['SHCCFLAGS'] = '$CCFLAGS'
+    env['SHCCFLAGS'] = SCons.Util.CLVar('$CCFLAGS')
     env['SHCCCOM']   = '$SHCC -WD $SHCCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES'
     env['CPPDEFPREFIX']  = '-D'
     env['CPPDEFSUFFIX']  = ''
diff --git a/src/engine/SCons/Tool/c++.py b/src/engine/SCons/Tool/c++.py
index 2ed7d44..8e0adfa 100644
--- a/src/engine/SCons/Tool/c++.py
+++ b/src/engine/SCons/Tool/c++.py
@@ -67,10 +67,10 @@ def generate(env):
         shared_obj.add_action(suffix, SCons.Defaults.ShCXXAction)
         
     env['CXX']        = 'c++'
-    env['CXXFLAGS']   = '$CCFLAGS'
+    env['CXXFLAGS']   = SCons.Util.CLVar('$CCFLAGS')
     env['CXXCOM']     = '$CXX $CXXFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES'
     env['SHCXX']      = '$CXX'
-    env['SHCXXFLAGS'] = '$CXXFLAGS'
+    env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS')
     env['SHCXXCOM']   = '$SHCXX $SHCXXFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES'
 
     env['CPPDEFPREFIX']  = '-D'
diff --git a/src/engine/SCons/Tool/cc.py b/src/engine/SCons/Tool/cc.py
index 18b62d2..f096065 100644
--- a/src/engine/SCons/Tool/cc.py
+++ b/src/engine/SCons/Tool/cc.py
@@ -53,10 +53,10 @@ def generate(env):
         shared_obj.add_action(suffix, SCons.Defaults.ShCAction)
         
     env['CC']        = 'cc'
-    env['CCFLAGS']   = ''
+    env['CCFLAGS']   = SCons.Util.CLVar('')
     env['CCCOM']     = '$CC $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES'
     env['SHCC']      = '$CC'
-    env['SHCCFLAGS'] = '$CCFLAGS'
+    env['SHCCFLAGS'] = SCons.Util.CLVar('$CCFLAGS')
     env['SHCCCOM']   = '$SHCC $SHCCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES'
 
     env['CPPDEFPREFIX']  = '-D'
diff --git a/src/engine/SCons/Tool/dvipdf.py b/src/engine/SCons/Tool/dvipdf.py
index b4da3c7..8c51ac0 100644
--- a/src/engine/SCons/Tool/dvipdf.py
+++ b/src/engine/SCons/Tool/dvipdf.py
@@ -34,6 +34,7 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Defaults
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for dvipdf to an Environment."""
@@ -45,11 +46,11 @@ def generate(env):
     bld.add_action('.dvi', '$PDFCOM')
 
     env['DVIPDF']      = 'dvipdf'
-    env['DVIPDFFLAGS'] = ''
+    env['DVIPDFFLAGS'] = SCons.Util.CLVar('')
     env['DVIPDFCOM']   = '$DVIPDF $DVIPDFFLAGS $SOURCES $TARGET'
 
     # Deprecated synonym.
-    env['PDFCOM']      = '$DVIPDFCOM'
+    env['PDFCOM']      = ['$DVIPDFCOM']
 
 def exists(env):
     return env.Detect('dvipdf')
diff --git a/src/engine/SCons/Tool/dvips.py b/src/engine/SCons/Tool/dvips.py
index f197b9b..d70d78d 100644
--- a/src/engine/SCons/Tool/dvips.py
+++ b/src/engine/SCons/Tool/dvips.py
@@ -35,6 +35,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Action
 import SCons.Defaults
+import SCons.Util
 
 PostScript = SCons.Builder.Builder(action = '$PSCOM',
                                    prefix = '$PSPREFIX',
@@ -47,7 +48,7 @@ def generate(env):
     env['BUILDERS']['PostScript'] = PostScript
     
     env['DVIPS']      = 'dvips'
-    env['DVIPSFLAGS'] = ''
+    env['DVIPSFLAGS'] = SCons.Util.CLVar('')
     env['PSCOM']      = '$DVIPS $DVIPSFLAGS -o $TARGET $SOURCES'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/f77.py b/src/engine/SCons/Tool/f77.py
index 4267096..83941f1 100644
--- a/src/engine/SCons/Tool/f77.py
+++ b/src/engine/SCons/Tool/f77.py
@@ -61,11 +61,11 @@ def generate(env):
         shared_obj.add_action(suffix, SCons.Defaults.ShF77PPAction)
 
     env['F77']        = env.Detect(compilers) or 'f77'
-    env['F77FLAGS']   = ''
+    env['F77FLAGS']   = SCons.Util.CLVar('')
     env['F77COM']     = '$F77 $F77FLAGS $_F77INCFLAGS -c -o $TARGET $SOURCES'
     env['F77PPCOM']   = '$F77 $F77FLAGS $CPPFLAGS $_CPPDEFFLAGS $_F77INCFLAGS -c -o $TARGET $SOURCES'
     env['SHF77']      = '$F77'
-    env['SHF77FLAGS'] = '$F77FLAGS'
+    env['SHF77FLAGS'] = SCons.Util.CLVar('$F77FLAGS')
     env['SHF77COM']   = '$SHF77 $SHF77FLAGS $_F77INCFLAGS -c -o $TARGET $SOURCES'
     env['SHF77PPCOM'] = '$SHF77 $SHF77FLAGS $CPPFLAGS $_CPPDEFFLAGS $_F77INCFLAGS -c -o $TARGET $SOURCES'
 
diff --git a/src/engine/SCons/Tool/g++.py b/src/engine/SCons/Tool/g++.py
index d641a6c..0576b90 100644
--- a/src/engine/SCons/Tool/g++.py
+++ b/src/engine/SCons/Tool/g++.py
@@ -34,7 +34,6 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import os.path
-import string
 import re
 
 import SCons.Defaults
@@ -55,27 +54,27 @@ def generate(env):
 
     # platform specific settings
     if env['PLATFORM'] == 'cygwin':
-        env['SHCXXFLAGS'] = '$CXXFLAGS'
+        env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS')
     elif env['PLATFORM'] == 'aix':
         # Original line from Christian Engel added -DPIC:
-        #env['SHCXXFLAGS'] = '$CXXFLAGS -DPIC -mminimal-toc'
-        env['SHCXXFLAGS'] = '$CXXFLAGS -mminimal-toc'
+        #env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS -DPIC -mminimal-toc')
+        env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS -mminimal-toc')
         env['STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME'] = 1
         env['SHOBJSUFFIX'] = '$OBJSUFFIX'
     elif env['PLATFORM'] == 'hpux':
         # Original line from Christian Engel added -DPIC:
-        #env['SHCXXFLAGS'] = '$CXXFLAGS -fPIC -DPIC'
-        env['SHCXXFLAGS'] = '$CXXFLAGS -fPIC'
+        #env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS -fPIC -DPIC')
+        env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS -fPIC')
         env['SHOBJSUFFIX'] = '.pic.o'
     elif env['PLATFORM'] == 'sunos':
         # Original line from Christian Engel added -DPIC:
-        #env['SHCXXFLAGS'] = '$CXXFLAGS -fPIC -DPIC'
-        env['SHCXXFLAGS'] = '$CXXFLAGS -fPIC'
+        #env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS -fPIC -DPIC')
+        env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS -fPIC')
         env['SHOBJSUFFIX'] = '.pic.o'
     else:
         # Original line from Christian Engel added -DPIC:
-        #env['SHCXXFLAGS'] = '$CXXFLAGS -fPIC -DPIC'
-        env['SHCXXFLAGS'] = '$CXXFLAGS -fPIC'
+        #env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS -fPIC -DPIC')
+        env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS -fPIC')
     # determine compiler version
     if env['CXX']:
         line = os.popen(env['CXX'] + ' --version').readline()
diff --git a/src/engine/SCons/Tool/gcc.py b/src/engine/SCons/Tool/gcc.py
index acbe440..761082e 100644
--- a/src/engine/SCons/Tool/gcc.py
+++ b/src/engine/SCons/Tool/gcc.py
@@ -33,6 +33,8 @@ selection method.
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.Util
+
 import cc
 
 compilers = ['gcc', 'cc']
@@ -43,9 +45,9 @@ def generate(env):
 
     env['CC'] = env.Detect(compilers) or 'gcc'
     if env['PLATFORM'] == 'cygwin':
-        env['SHCCFLAGS'] = '$CCFLAGS'
+        env['SHCCFLAGS'] = SCons.Util.CLVar('$CCFLAGS')
     else:
-        env['SHCCFLAGS'] = ['$CCFLAGS', '-fPIC']
+        env['SHCCFLAGS'] = SCons.Util.CLVar('$CCFLAGS -fPIC')
 
 def exists(env):
     return env.Detect(compilers)
diff --git a/src/engine/SCons/Tool/gnulink.py b/src/engine/SCons/Tool/gnulink.py
index 3c3bba1..0e75304 100644
--- a/src/engine/SCons/Tool/gnulink.py
+++ b/src/engine/SCons/Tool/gnulink.py
@@ -33,6 +33,8 @@ selection method.
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.Util
+
 import link
 
 linkers = ['g++', 'gcc']
@@ -42,7 +44,7 @@ def generate(env):
     link.generate(env)
 
     if env['PLATFORM'] == 'hpux':
-        env['SHLINKFLAGS'] = '$LINKFLAGS -shared -fPIC'
+        env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -shared -fPIC')
     
 def exists(env):
     return env.Detect(linkers)
diff --git a/src/engine/SCons/Tool/gs.py b/src/engine/SCons/Tool/gs.py
index 79d50e4..2666189 100644
--- a/src/engine/SCons/Tool/gs.py
+++ b/src/engine/SCons/Tool/gs.py
@@ -35,6 +35,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Defaults
 import SCons.Platform
+import SCons.Util
 
 # Ghostscript goes by different names on different platforms...
 platform = SCons.Platform.platform_default()
@@ -58,7 +59,7 @@ def generate(env):
     bld.add_action('.ps', '$GSCOM')
 
     env['GS']      = gs
-    env['GSFLAGS'] = '-dNOPAUSE -dBATCH -sDEVICE=pdfwrite'
+    env['GSFLAGS'] = SCons.Util.CLVar('-dNOPAUSE -dBATCH -sDEVICE=pdfwrite')
     env['GSCOM']   = '$GS $GSFLAGS -sOutputFile=$TARGET $SOURCES'
 
 
diff --git a/src/engine/SCons/Tool/hpc++.py b/src/engine/SCons/Tool/hpc++.py
index 4ed1ba0..a1b3e97 100644
--- a/src/engine/SCons/Tool/hpc++.py
+++ b/src/engine/SCons/Tool/hpc++.py
@@ -36,6 +36,8 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 import os.path
 import string
 
+import SCons.Util
+
 cplusplus = __import__('c++', globals(), locals(), [])
 
 acc = None
@@ -66,9 +68,9 @@ def generate(env):
             env['CXXVERSION'] = string.split(line)[-1]
 
         if env['PLATFORM'] == 'cygwin':
-            env['SHCXXFLAGS'] = '$CXXFLAGS'
+            env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS')
         else:
-            env['SHCXXFLAGS'] = '$CXXFLAGS +Z'
+            env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS +Z')
 
 def exists(env):
     return acc
diff --git a/src/engine/SCons/Tool/hplink.py b/src/engine/SCons/Tool/hplink.py
index 2c7b55c..f3d03c9 100644
--- a/src/engine/SCons/Tool/hplink.py
+++ b/src/engine/SCons/Tool/hplink.py
@@ -35,6 +35,8 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 import os
 import os.path
 
+import SCons.Util
+
 import link
 
 ccLinker = None
@@ -59,8 +61,8 @@ def generate(env):
     """
     link.generate(env)
     
-    env['LINKFLAGS']   = '-Wl,+s -Wl,+vnocompatwarnings'
-    env['SHLINKFLAGS'] = '$LINKFLAGS -b'
+    env['LINKFLAGS']   = SCons.Util.CLVar('-Wl,+s -Wl,+vnocompatwarnings')
+    env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -b')
     env['SHLIBSUFFIX'] = '.sl'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/icc.py b/src/engine/SCons/Tool/icc.py
index 20bf17c..4a553a0 100644
--- a/src/engine/SCons/Tool/icc.py
+++ b/src/engine/SCons/Tool/icc.py
@@ -33,6 +33,8 @@ selection method.
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.Util
+
 import cc
 
 def generate(env):
diff --git a/src/engine/SCons/Tool/ifl.py b/src/engine/SCons/Tool/ifl.py
index 1b0cd33..04c9d39 100644
--- a/src/engine/SCons/Tool/ifl.py
+++ b/src/engine/SCons/Tool/ifl.py
@@ -33,6 +33,8 @@ selection method.
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.Util
+
 import f77
 
 def generate(env):
@@ -40,11 +42,11 @@ def generate(env):
     f77.generate(env)
 
     env['F77']        = 'ifl'
-    env['F77FLAGS']   = ''
+    env['F77FLAGS']   = SCons.Util.CLVar('')
     env['F77COM']     = '$F77 $F77FLAGS $_F77INCFLAGS /c $SOURCES /Fo$TARGET'
     env['F77PPCOM']   = '$F77 $F77FLAGS $CPPFLAGS $_CPPDEFFLAGS $_F77INCFLAGS /c $SOURCES /Fo$TARGET'
     env['SHF77']      = '$F77'
-    env['SHF77FLAGS'] = '$F77FLAGS'
+    env['SHF77FLAGS'] = SCons.Util.CLVar('$F77FLAGS')
     env['SHF77COM']   = '$SHF77 $SHF77FLAGS $_F77INCFLAGS /c $SOURCES /Fo$TARGET'
     env['SHF77PPCOM'] = '$SHF77 $SHF77FLAGS $CPPFLAGS $_CPPDEFFLAGS $_F77INCFLAGS /c $SOURCES /Fo$TARGET'
 
diff --git a/src/engine/SCons/Tool/ilink.py b/src/engine/SCons/Tool/ilink.py
index 739dd17..180e57a 100644
--- a/src/engine/SCons/Tool/ilink.py
+++ b/src/engine/SCons/Tool/ilink.py
@@ -35,13 +35,14 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Defaults
 import SCons.Tool
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for ilink to an Environment."""
     SCons.Tool.createProgBuilder(env)
     
     env['LINK']        = 'ilink'
-    env['LINKFLAGS']   = ''
+    env['LINKFLAGS']   = SCons.Util.CLVar('')
     env['LINKCOM']     = '$LINK $LINKFLAGS /O:$TARGET $SOURCES $( $_LIBDIRFLAGS $) $_LIBFLAGS'
     env['LIBDIRPREFIX']='/LIBPATH:'
     env['LIBDIRSUFFIX']=''
diff --git a/src/engine/SCons/Tool/ilink32.py b/src/engine/SCons/Tool/ilink32.py
index 35d1a66..a667b75 100644
--- a/src/engine/SCons/Tool/ilink32.py
+++ b/src/engine/SCons/Tool/ilink32.py
@@ -31,6 +31,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Tool
 import SCons.Tool.bcc32
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for ilink to an
@@ -38,7 +39,7 @@ def generate(env):
     SCons.Tool.createProgBuilder(env)
 
     env['LINK']        = '$CC'
-    env['LINKFLAGS']   = ''
+    env['LINKFLAGS']   = SCons.Util.CLVar('')
     env['LINKCOM']     = '$LINK -q $LINKFLAGS $SOURCES $LIBS'
     env['LIBDIRPREFIX']=''
     env['LIBDIRSUFFIX']=''
diff --git a/src/engine/SCons/Tool/jar.py b/src/engine/SCons/Tool/jar.py
index 5fcb205..7934ed2 100644
--- a/src/engine/SCons/Tool/jar.py
+++ b/src/engine/SCons/Tool/jar.py
@@ -37,6 +37,7 @@ import glob
 import os.path
 
 import SCons.Builder
+import SCons.Util
 
 def jarSources(target, source, env, for_signature):
     """Only include sources that are not a manifest file."""
@@ -63,13 +64,14 @@ def jarManifest(target, source, env, for_signature):
 def jarFlags(target, source, env, for_signature):
     """If we have a manifest, make sure that the 'm'
     flag is specified."""
+    jarflags = env.subst('$JARFLAGS')
     for src in source:
         contents = src.get_contents()
         if contents[:16] == "Manifest-Version":
-            if not 'm' in env['JARFLAGS']:
-                return env['JARFLAGS'] + 'm'
+            if not 'm' in jarflags:
+                return jarflags + 'm'
             break
-    return env['JARFLAGS']
+    return jarflags
 
 def jarChdir(target, source, env, for_signature):
     """If we have an Environment variable by the name
@@ -91,7 +93,7 @@ def generate(env):
         env['BUILDERS']['Jar'] = JarBuilder
 
     env['JAR']        = 'jar'
-    env['JARFLAGS']   = 'cf'
+    env['JARFLAGS']   = SCons.Util.CLVar('cf')
     env['_JARFLAGS']  = jarFlags
     env['_JARMANIFEST'] = jarManifest
     env['_JARSOURCES'] = jarSources
diff --git a/src/engine/SCons/Tool/javac.py b/src/engine/SCons/Tool/javac.py
index 3d4df10..b56a118 100644
--- a/src/engine/SCons/Tool/javac.py
+++ b/src/engine/SCons/Tool/javac.py
@@ -41,6 +41,7 @@ import string
 import SCons.Builder
 from SCons.Node.FS import _my_normcase
 from SCons.Tool.JavaCommon import parse_java_file
+import SCons.Util
 
 def classname(path):
     """Turn a string (path name) into a Java class name."""
@@ -100,7 +101,7 @@ def generate(env):
     env['BUILDERS']['Java'] = JavaBuilder
 
     env['JAVAC']            = 'javac'
-    env['JAVACFLAGS']       = ''
+    env['JAVACFLAGS']       = SCons.Util.CLVar('')
     env['JAVACCOM']         = '$JAVAC $JAVACFLAGS -d ${TARGET.attributes.java_classdir} -sourcepath ${SOURCE.dir.rdir()} $SOURCES'
     env['JAVACLASSSUFFIX']  = '.class'
     env['JAVASUFFIX']       = '.java'
diff --git a/src/engine/SCons/Tool/javah.py b/src/engine/SCons/Tool/javah.py
index fe8c82d..c35f909 100644
--- a/src/engine/SCons/Tool/javah.py
+++ b/src/engine/SCons/Tool/javah.py
@@ -40,6 +40,7 @@ import string
 import SCons.Builder
 import SCons.Node.FS
 import SCons.Tool.javac
+import SCons.Util
 
 def emit_java_headers(target, source, env):
     """Create and return lists of Java stub header files that will
@@ -118,7 +119,7 @@ def generate(env):
 
     env['_JAVAHOUTFLAG']    = JavaHOutFlagGenerator
     env['JAVAH']            = 'javah'
-    env['JAVAHFLAGS']       = ''
+    env['JAVAHFLAGS']       = SCons.Util.CLVar('')
     env['JAVAHCOM']         = '$JAVAH $JAVAHFLAGS $_JAVAHOUTFLAG -classpath ${SOURCE.attributes.java_classdir} ${SOURCES.attributes.java_classname}'
     env['JAVACLASSSUFFIX']  = '.class'
 
diff --git a/src/engine/SCons/Tool/latex.py b/src/engine/SCons/Tool/latex.py
index d9b912c..7bbec6f 100644
--- a/src/engine/SCons/Tool/latex.py
+++ b/src/engine/SCons/Tool/latex.py
@@ -35,6 +35,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Action
 import SCons.Defaults
+import SCons.Util
 
 LaTeXAction = SCons.Action.Action('$LATEXCOM')
 
@@ -51,7 +52,7 @@ def generate(env):
     bld.add_action('.latex', LaTeXAction)
 
     env['LATEX']      = 'latex'
-    env['LATEXFLAGS'] = ''
+    env['LATEXFLAGS'] = SCons.Util.CLVar('')
     env['LATEXCOM']   = '$LATEX $LATEXFLAGS $SOURCES'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/lex.py b/src/engine/SCons/Tool/lex.py
index 9ef2167..004d0da 100644
--- a/src/engine/SCons/Tool/lex.py
+++ b/src/engine/SCons/Tool/lex.py
@@ -35,6 +35,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Defaults
 import SCons.Tool
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for lex to an Environment."""
@@ -44,7 +45,7 @@ def generate(env):
     cxx_file.add_action('.ll', '$LEXCOM')
 
     env['LEX']      = env.Detect('flex') or 'lex'
-    env['LEXFLAGS'] = ''
+    env['LEXFLAGS'] = SCons.Util.CLVar('')
     env['LEXCOM']   = '$LEX $LEXFLAGS -t $SOURCES > $TARGET'
     
 def exists(env):
diff --git a/src/engine/SCons/Tool/link.py b/src/engine/SCons/Tool/link.py
index da672c1..cc0d4f4 100644
--- a/src/engine/SCons/Tool/link.py
+++ b/src/engine/SCons/Tool/link.py
@@ -50,12 +50,12 @@ def generate(env):
     SCons.Tool.createProgBuilder(env)
     
     env['SHLINK']      = '$LINK'
-    env['SHLINKFLAGS'] = '$LINKFLAGS -shared'
+    env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -shared')
     env['SHLINKCOM']   = '$SHLINK $SHLINKFLAGS -o $TARGET $SOURCES $_LIBDIRFLAGS $_LIBFLAGS'
     env['SHLIBEMITTER']= None
     env['SMARTLINK']   = smart_link
     env['LINK']        = "$SMARTLINK"
-    env['LINKFLAGS']   = ''
+    env['LINKFLAGS']   = SCons.Util.CLVar('')
     env['LINKCOM']     = '$LINK $LINKFLAGS -o $TARGET $SOURCES $_LIBDIRFLAGS $_LIBFLAGS'
     env['LIBDIRPREFIX']='-L'
     env['LIBDIRSUFFIX']=''
diff --git a/src/engine/SCons/Tool/linkloc.py b/src/engine/SCons/Tool/linkloc.py
index 313a16b..a5b2bdd 100644
--- a/src/engine/SCons/Tool/linkloc.py
+++ b/src/engine/SCons/Tool/linkloc.py
@@ -35,7 +35,6 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import os.path
-import string
 import re
 
 import SCons.Action
@@ -84,11 +83,11 @@ def generate(env):
 
     env['SUBST_CMD_FILE'] = LinklocGenerator
     env['SHLINK']      = '$LINK'
-    env['SHLINKFLAGS'] = '$LINKFLAGS'
+    env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS')
     env['SHLINKCOM']   = '${SUBST_CMD_FILE("$SHLINK $SHLINKFLAGS $( $_LIBDIRFLAGS $) $_LIBFLAGS -dll $TARGET $SOURCES")}'
     env['SHLIBEMITTER']= None
     env['LINK']        = "linkloc"
-    env['LINKFLAGS']   = ''
+    env['LINKFLAGS']   = SCons.Util.CLVar('')
     env['LINKCOM']     = '${SUBST_CMD_FILE("$LINK $LINKFLAGS $( $_LIBDIRFLAGS $) $_LIBFLAGS -exe $TARGET $SOURCES")}'
     env['LIBDIRPREFIX']='-libpath '
     env['LIBDIRSUFFIX']=''
diff --git a/src/engine/SCons/Tool/m4.py b/src/engine/SCons/Tool/m4.py
index 0c83c66..3fd2d66 100644
--- a/src/engine/SCons/Tool/m4.py
+++ b/src/engine/SCons/Tool/m4.py
@@ -34,6 +34,7 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Builder
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for m4 to an Environment."""
@@ -47,7 +48,7 @@ def generate(env):
     # The src_suffix setup is like so: file.c.m4 -> file.c,
     # file.cpp.m4 -> file.cpp etc.
     env['M4']      = 'm4'
-    env['M4FLAGS'] = '-E'
+    env['M4FLAGS'] = SCons.Util.CLVar('-E')
     env['M4COM']   = 'cd ${SOURCE.rsrcdir} && $M4 $M4FLAGS < ${SOURCE.file} > ${TARGET.abspath}'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/masm.py b/src/engine/SCons/Tool/masm.py
index 92f4c35..1bb9f95 100644
--- a/src/engine/SCons/Tool/masm.py
+++ b/src/engine/SCons/Tool/masm.py
@@ -37,6 +37,7 @@ import os.path
 
 import SCons.Defaults
 import SCons.Tool
+import SCons.Util
 
 ASSuffixes = ['.s', '.asm', '.ASM']
 ASPPSuffixes = ['.spp', '.SPP']
@@ -58,7 +59,7 @@ def generate(env):
         shared_obj.add_action(suffix, SCons.Defaults.ASPPAction)
 
     env['AS']        = 'ml'
-    env['ASFLAGS']   = '/nologo'
+    env['ASFLAGS']   = SCons.Util.CLVar('/nologo')
     env['ASCOM']     = '$AS $ASFLAGS /c /Fo$TARGET $SOURCES'
     env['ASPPCOM']   = '$CC $ASFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS /c /Fo$TARGET $SOURCES'
     env['STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME'] = 1
diff --git a/src/engine/SCons/Tool/midl.py b/src/engine/SCons/Tool/midl.py
index fe424fc..2efabcc 100644
--- a/src/engine/SCons/Tool/midl.py
+++ b/src/engine/SCons/Tool/midl.py
@@ -64,8 +64,8 @@ def generate(env):
     """Add Builders and construction variables for midl to an Environment."""
 
     env['MIDL']          = 'MIDL.EXE'
-    env['MIDLFLAGS']     = '/nologo'
-    env['MIDLCOM']       = "$MIDL $MIDLFLAGS /tlb ${TARGETS[0]} /h ${TARGETS[1]} /iid ${TARGETS[2]} /proxy ${TARGETS[3]} /dlldata ${TARGETS[4]} $SOURCE 2> NUL"
+    env['MIDLFLAGS']     = SCons.Util.CLVar('/nologo')
+    env['MIDLCOM']       = '$MIDL $MIDLFLAGS /tlb ${TARGETS[0]} /h ${TARGETS[1]} /iid ${TARGETS[2]} /proxy ${TARGETS[3]} /dlldata ${TARGETS[4]} $SOURCE 2> NUL'
     env['BUILDERS']['TypeLibrary'] = midl_builder
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/mingw.py b/src/engine/SCons/Tool/mingw.py
index bc3693d..ac4d969 100644
--- a/src/engine/SCons/Tool/mingw.py
+++ b/src/engine/SCons/Tool/mingw.py
@@ -33,11 +33,12 @@ selection method.
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
-import os.path
 import os
+import os.path
+import string
+
 import SCons.Tool
 import SCons.Util
-import string
 
 # This is what we search for to find mingw:
 key_program = 'mingw32-gcc'
@@ -47,7 +48,7 @@ def find(env):
     return env.WhereIs(key_program) or SCons.Util.WhereIs(key_program)
 
 def shlib_generator(target, source, env, for_signature):
-    cmd = ['$SHLINK', '$SHLINKFLAGS'] 
+    cmd = SCons.Util.CLVar('$SHLINK', '$SHLINKFLAGS') 
 
     dll = env.FindIxes(target, 'SHLIBPREFIX', 'SHLIBSUFFIX')
     if dll: cmd.extend(['-o', dll])
@@ -117,10 +118,10 @@ def generate(env):
 
     #... but a few things differ:
     env['CC'] = 'gcc'
-    env['SHCCFLAGS'] = '$CCFLAGS'
+    env['SHCCFLAGS'] = SCons.Util.CLVar('$CCFLAGS')
     env['CXX'] = 'g++'
-    env['SHCXXFLAGS'] = '$CXXFLAGS'
-    env['SHLINKFLAGS'] = '$LINKFLAGS -shared'
+    env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS')
+    env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -shared')
     env['SHLINKCOM']   = shlib_action
     env['SHLIBEMITTER']= shlib_emitter
     env['LINK'] = 'g++'
@@ -131,8 +132,8 @@ def generate(env):
     env['STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME'] = 1
 
     env['RC'] = 'windres'
-    env['RCFLAGS'] = ''
-    env['RCINCFLAGS'] = '$( ${_concat(RCINCPREFIX, CPPPATH, RCINCSUFFIX, __env__, RDirs)} $)'
+    env['RCFLAGS'] = SCons.Util.CLVar('')
+    env['RCINCFLAGS'] = SCons.Util.CLVar('$( ${_concat(RCINCPREFIX, CPPPATH, RCINCSUFFIX, __env__, RDirs)} $)')
     env['RCINCPREFIX'] = '--include-dir '
     env['RCINCSUFFIX'] = ''
     env['RCCOM'] = '$RC $RCINCFLAGS $RCFLAGS -i $SOURCE -o $TARGET'
diff --git a/src/engine/SCons/Tool/mslib.py b/src/engine/SCons/Tool/mslib.py
index 646cbde..1075c56 100644
--- a/src/engine/SCons/Tool/mslib.py
+++ b/src/engine/SCons/Tool/mslib.py
@@ -37,6 +37,7 @@ import SCons.Defaults
 import SCons.Tool
 import SCons.Tool.msvs
 import SCons.Tool.msvc
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for lib to an Environment."""
@@ -57,7 +58,7 @@ def generate(env):
         pass
 
     env['AR']          = 'lib'
-    env['ARFLAGS']     = '/nologo'
+    env['ARFLAGS']     = SCons.Util.CLVar('/nologo')
     env['ARCOM']       = "${TEMPFILE('$AR $ARFLAGS /OUT:$TARGET $SOURCES')}"
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/mslink.py b/src/engine/SCons/Tool/mslink.py
index 282fb22..fd53757 100644
--- a/src/engine/SCons/Tool/mslink.py
+++ b/src/engine/SCons/Tool/mslink.py
@@ -34,16 +34,15 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import os.path
-import string
 
 import SCons.Action
 import SCons.Defaults
 import SCons.Errors
-import SCons.Util
+import SCons.Platform.win32
 import SCons.Tool
-import SCons.Tool.msvs
 import SCons.Tool.msvc
-import SCons.Platform.win32
+import SCons.Tool.msvs
+import SCons.Util
 
 def pdbGenerator(env, target, source, for_signature):
     if target and env.has_key('PDB') and env['PDB']:
@@ -137,13 +136,13 @@ def generate(env):
     SCons.Tool.createProgBuilder(env)
     
     env['SHLINK']      = '$LINK'
-    env['SHLINKFLAGS'] = '$LINKFLAGS /dll'
+    env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS /dll')
     env['_SHLINK_TARGETS'] = win32ShlinkTargets
     env['_SHLINK_SOURCES'] = win32ShlinkSources
     env['SHLINKCOM']   =  compositeLinkAction
     env['SHLIBEMITTER']= win32LibEmitter
     env['LINK']        = 'link'
-    env['LINKFLAGS']   = '/nologo'
+    env['LINKFLAGS']   = SCons.Util.CLVar('/nologo')
     env['_PDB'] = pdbGenerator
     env['LINKCOM'] = '${TEMPFILE("$LINK $LINKFLAGS /OUT:$TARGET $( $_LIBDIRFLAGS $) $_LIBFLAGS $_PDB $SOURCES")}'
     env['PROGEMITTER'] = prog_emitter
diff --git a/src/engine/SCons/Tool/msvc.py b/src/engine/SCons/Tool/msvc.py
index 40f8b40..e2c0b65 100644
--- a/src/engine/SCons/Tool/msvc.py
+++ b/src/engine/SCons/Tool/msvc.py
@@ -34,18 +34,18 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import os.path
+import re
 import string
 import types
-import re
 
 import SCons.Action
-import SCons.Tool
-import SCons.Errors
-import SCons.Warnings
 import SCons.Builder
-import SCons.Util
+import SCons.Errors
 import SCons.Platform.win32
+import SCons.Tool
 import SCons.Tool.msvs
+import SCons.Util
+import SCons.Warnings
 
 CSuffixes = ['.c', '.C']
 CXXSuffixes = ['.cc', '.cpp', '.cxx', '.c++', '.C++']
@@ -395,20 +395,20 @@ def generate(env):
         static_obj.add_action(suffix, SCons.Defaults.CXXAction)
         shared_obj.add_action(suffix, SCons.Defaults.ShCXXAction)
 
-    env['CCPDBFLAGS'] = '${(PDB and "/Zi /Fd%s"%File(PDB)) or ""}'
-    env['CCPCHFLAGS'] = '${(PCH and "/Yu%s /Fp%s"%(PCHSTOP or "",File(PCH))) or ""}'
+    env['CCPDBFLAGS'] = SCons.Util.CLVar(['${(PDB and "/Zi /Fd%s"%File(PDB)) or ""}'])
+    env['CCPCHFLAGS'] = SCons.Util.CLVar(['${(PCH and "/Yu%s /Fp%s"%(PCHSTOP or "",File(PCH))) or ""}'])
     env['CCCOMFLAGS'] = '$CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS /c $SOURCES /Fo$TARGET $CCPCHFLAGS $CCPDBFLAGS'
     env['CC']         = 'cl'
-    env['CCFLAGS']    = '/nologo'
-    env['CCCOM']      = '$CC $CCFLAGS $CCCOMFLAGS' 
+    env['CCFLAGS']    = SCons.Util.CLVar('/nologo')
+    env['CCCOM']      = '$CC $CCFLAGS $CCCOMFLAGS'
     env['SHCC']       = '$CC'
-    env['SHCCFLAGS']  = '$CCFLAGS'
+    env['SHCCFLAGS']  = SCons.Util.CLVar('$CCFLAGS')
     env['SHCCCOM']    = '$SHCC $SHCCFLAGS $CCCOMFLAGS'
     env['CXX']        = '$CC'
-    env['CXXFLAGS']   = ['$CCFLAGS', '$(', '/TP', '$)']
+    env['CXXFLAGS']   = SCons.Util.CLVar('$CCFLAGS $( /TP $)')
     env['CXXCOM']     = '$CXX $CXXFLAGS $CCCOMFLAGS'
     env['SHCXX']      = '$CXX'
-    env['SHCXXFLAGS'] = '$CXXFLAGS'
+    env['SHCXXFLAGS'] = SCons.Util.CLVar('$CXXFLAGS')
     env['SHCXXCOM']   = '$SHCXX $SHCXXFLAGS $CCCOMFLAGS'
     env['CPPDEFPREFIX']  = '/D'
     env['CPPDEFSUFFIX']  = ''
@@ -419,7 +419,7 @@ def generate(env):
     env['STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME'] = 1
 
     env['RC'] = 'rc'
-    env['RCFLAGS'] = ''
+    env['RCFLAGS'] = SCons.Util.CLVar('')
     env['RCCOM'] = '$RC $_CPPDEFFLAGS $_CPPINCFLAGS $RCFLAGS /fo$TARGET $SOURCES'
     CScan = env.get_scanner('.c')
     if CScan:
diff --git a/src/engine/SCons/Tool/nasm.py b/src/engine/SCons/Tool/nasm.py
index 6a2fc36..84075ba 100644
--- a/src/engine/SCons/Tool/nasm.py
+++ b/src/engine/SCons/Tool/nasm.py
@@ -37,6 +37,7 @@ import os.path
 
 import SCons.Defaults
 import SCons.Tool
+import SCons.Util
 
 ASSuffixes = ['.s', '.asm', '.ASM']
 ASPPSuffixes = ['.spp', '.SPP']
@@ -56,7 +57,7 @@ def generate(env):
         static_obj.add_action(suffix, SCons.Defaults.ASPPAction)
 
     env['AS']        = 'nasm'
-    env['ASFLAGS']   = ''
+    env['ASFLAGS']   = SCons.Util.CLVar('')
     env['ASCOM']     = '$AS $ASFLAGS -o $TARGET $SOURCES'
     env['ASPPCOM']   = '$CC $ASFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES'
 
diff --git a/src/engine/SCons/Tool/pdflatex.py b/src/engine/SCons/Tool/pdflatex.py
index 1ae606e..b1a559a 100644
--- a/src/engine/SCons/Tool/pdflatex.py
+++ b/src/engine/SCons/Tool/pdflatex.py
@@ -35,6 +35,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Action
 import SCons.Defaults
+import SCons.Util
 
 PDFLaTeXAction = SCons.Action.Action('$PDFLATEXCOM')
 
@@ -50,7 +51,7 @@ def generate(env):
     bld.add_action('.latex', PDFLaTeXAction)
 
     env['PDFLATEX']      = 'pdflatex'
-    env['PDFLATEXFLAGS'] = ''
+    env['PDFLATEXFLAGS'] = SCons.Util.CLVar('')
     env['PDFLATEXCOM']   = '$PDFLATEX $PDFLATEXFLAGS $SOURCES $TARGET'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/pdftex.py b/src/engine/SCons/Tool/pdftex.py
index 14b3d95..3d2add0 100644
--- a/src/engine/SCons/Tool/pdftex.py
+++ b/src/engine/SCons/Tool/pdftex.py
@@ -34,6 +34,7 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Defaults
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for pdftex to an Environment."""
@@ -46,7 +47,7 @@ def generate(env):
     bld.add_action('.tex', '$PDFTEXCOM')
 
     env['PDFTEX']      = 'pdftex'
-    env['PDFTEXFLAGS'] = ''
+    env['PDFTEXFLAGS'] = SCons.Util.CLVar('')
     env['PDFTEXCOM']   = '$PDFTEX $PDFTEXFLAGS $SOURCES $TARGET'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/qt.py b/src/engine/SCons/Tool/qt.py
index 9969e02..693f77e 100644
--- a/src/engine/SCons/Tool/qt.py
+++ b/src/engine/SCons/Tool/qt.py
@@ -34,9 +34,9 @@ selection method.
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
-import sys
 import os.path
 import re
+import sys
 
 import SCons.Defaults
 import SCons.Tool
@@ -154,10 +154,10 @@ def generate(env):
 
     # Some QT specific flags. I don't expect someone wants to
     # manipulate those ...
-    env['QT_UICIMPLFLAGS'] = ''
-    env['QT_UICDECLFLAGS'] = ''
-    env['QT_MOCFROMHFLAGS'] = ''
-    env['QT_MOCFROMCXXFLAGS'] = '-i'
+    env['QT_UICIMPLFLAGS'] = SCons.Util.CLVar('')
+    env['QT_UICDECLFLAGS'] = SCons.Util.CLVar('')
+    env['QT_MOCFROMHFLAGS'] = SCons.Util.CLVar('')
+    env['QT_MOCFROMCXXFLAGS'] = SCons.Util.CLVar('-i')
 
     # Suffixes for the headers / sources to generate
     env['QT_HSUFFIX'] = '.h'
diff --git a/src/engine/SCons/Tool/rmic.py b/src/engine/SCons/Tool/rmic.py
index 79cc316..565dc9e 100644
--- a/src/engine/SCons/Tool/rmic.py
+++ b/src/engine/SCons/Tool/rmic.py
@@ -39,6 +39,7 @@ import string
 
 import SCons.Builder
 import SCons.Node.FS
+import SCons.Util
 
 def emit_rmic_classes(target, source, env):
     """Create and return lists of Java RMI stub and skeleton
@@ -101,7 +102,7 @@ def generate(env):
     env['BUILDERS']['RMIC'] = RMICBuilder
 
     env['RMIC']            = 'rmic'
-    env['RMICFLAGS']       = ''
+    env['RMICFLAGS']       = SCons.Util.CLVar('')
     env['RMICCOM']         = '$RMIC $RMICFLAGS -d ${TARGET.attributes.java_lookupdir} -classpath ${SOURCE.attributes.java_classdir} ${SOURCES.attributes.java_classname}'
     env['JAVACLASSSUFFIX']  = '.class'
 
diff --git a/src/engine/SCons/Tool/sgiar.py b/src/engine/SCons/Tool/sgiar.py
index 079ec8c..1409d03 100644
--- a/src/engine/SCons/Tool/sgiar.py
+++ b/src/engine/SCons/Tool/sgiar.py
@@ -37,6 +37,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Defaults
 import SCons.Tool
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for ar to an Environment."""
@@ -44,15 +45,15 @@ def generate(env):
     
     if env.Detect('CC'):
         env['AR']          = 'CC'
-        env['ARFLAGS']     = '-ar'
+        env['ARFLAGS']     = SCons.Util.CLVar('-ar')
         env['ARCOM']       = '$AR $ARFLAGS -o $TARGET $SOURCES'
     else:
         env['AR']          = 'ar'
-        env['ARFLAGS']     = 'r'
+        env['ARFLAGS']     = SCons.Util.CLVar('r')
         env['ARCOM']       = '$AR $ARFLAGS $TARGET $SOURCES'
         
     env['SHLINK']      = '$LINK'
-    env['SHLINKFLAGS'] = '$LINKFLAGS -shared'
+    env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -shared')
     env['SHLINKCOM']   = '$SHLINK $SHLINKFLAGS -o $TARGET $SOURCES $_LIBDIRFLAGS $_LIBFLAGS'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/sgic++.py b/src/engine/SCons/Tool/sgic++.py
index a8c9186..9081044 100644
--- a/src/engine/SCons/Tool/sgic++.py
+++ b/src/engine/SCons/Tool/sgic++.py
@@ -7,10 +7,35 @@ It will usually be imported through the generic SCons.Tool.Tool()
 selection method.
 
 """
-__revision__ = ""
+
+#
+# __COPYRIGHT__
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import os.path
-import string
+
+import SCons.Util
 
 cplusplus = __import__('c++', globals(), locals(), [])
 
@@ -20,7 +45,7 @@ def generate(env):
     cplusplus.generate(env)
 
     env['CXX']         = 'CC'
-    env['CXXFLAGS']    = ['$CCFLAGS', '-LANG:std']
+    env['CXXFLAGS']    = SCons.Util.CLVar('$CCFLAGS -LANG:std')
     env['SHCXX']       = 'CC'
     env['SHOBJSUFFIX'] = '.o'
     env['STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME'] = 1
diff --git a/src/engine/SCons/Tool/sgilink.py b/src/engine/SCons/Tool/sgilink.py
index 5643c08..80cfcf4 100644
--- a/src/engine/SCons/Tool/sgilink.py
+++ b/src/engine/SCons/Tool/sgilink.py
@@ -33,6 +33,8 @@ selection method.
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.Util
+
 import link
 
 linkers = ['CC', 'cc']
@@ -42,7 +44,7 @@ def generate(env):
     link.generate(env)
     
     env['LINK'] = env.Detect(linkers) or 'cc'
-    env['SHLINKFLAGS'] = '$LINKFLAGS -shared'
+    env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -shared')
 
 def exists(env):
     return env.Detect(linkers)
diff --git a/src/engine/SCons/Tool/sunar.py b/src/engine/SCons/Tool/sunar.py
index 5d44b60..36a6984 100644
--- a/src/engine/SCons/Tool/sunar.py
+++ b/src/engine/SCons/Tool/sunar.py
@@ -36,6 +36,7 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Defaults
 import SCons.Tool
+import SCons.Util
 
 def generate(env):
     """Add Builders and construction variables for ar to an Environment."""
@@ -43,15 +44,15 @@ def generate(env):
     
     if env.Detect('CC'):
         env['AR']          = 'CC'
-        env['ARFLAGS']     = '-xar'
+        env['ARFLAGS']     = SCons.Util.CLVar('-xar')
         env['ARCOM']       = '$AR $ARFLAGS -o $TARGET $SOURCES'
     else:
         env['AR']          = 'ar'
-        env['ARFLAGS']     = 'r'
+        env['ARFLAGS']     = SCons.Util.CLVar('r')
         env['ARCOM']       = '$AR $ARFLAGS $TARGET $SOURCES'
 
     env['SHLINK']      = '$LINK'
-    env['SHLINKFLAGS'] = '$LINKFLAGS -G'
+    env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -G')
     env['SHLINKCOM']   = '$SHLINK $SHLINKFLAGS -o $TARGET $SOURCES $_LIBDIRFLAGS $_LIBFLAGS'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/sunlink.py b/src/engine/SCons/Tool/sunlink.py
index 53dd410..88624ca 100644
--- a/src/engine/SCons/Tool/sunlink.py
+++ b/src/engine/SCons/Tool/sunlink.py
@@ -35,6 +35,8 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 import os
 import os.path
 
+import SCons.Util
+
 import link
 
 ccLinker = None
@@ -56,7 +58,7 @@ def generate(env):
     """Add Builders and construction variables for Forte to an Environment."""
     link.generate(env)
     
-    env['SHLINKFLAGS'] = '$LINKFLAGS -G'
+    env['SHLINKFLAGS'] = SCons.Util.CLVar('$LINKFLAGS -G')
 
 def exists(env):
     return ccLinker
diff --git a/src/engine/SCons/Tool/swig.py b/src/engine/SCons/Tool/swig.py
index 9dcfad4..b58fadc 100644
--- a/src/engine/SCons/Tool/swig.py
+++ b/src/engine/SCons/Tool/swig.py
@@ -34,13 +34,13 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import os.path
-import string
 
 import SCons.Defaults
 import SCons.Tool
+import SCons.Util
 
 def swigSuffixEmitter(env, source):
-    if '-c++' in string.split(env.subst("$SWIGFLAGS")):
+    if '-c++' in SCons.Util.CLVar(env.subst("$SWIGFLAGS")):
         return '$SWIGCXXFILESUFFIX'
     else:
         return '$SWIGCFILESUFFIX'
@@ -56,7 +56,7 @@ def generate(env):
     cxx_file.add_action('.i', '$SWIGCOM')
 
     env['SWIG']              = 'swig'
-    env['SWIGFLAGS']         = ''
+    env['SWIGFLAGS']         = SCons.Util.CLVar('')
     env['SWIGCFILESUFFIX']   = '_wrap$CFILESUFFIX'
     env['SWIGCXXFILESUFFIX'] = '_wrap$CXXFILESUFFIX'
     env['SWIGCOM']           = '$SWIG $SWIGFLAGS -o $TARGET $SOURCES'
diff --git a/src/engine/SCons/Tool/tar.py b/src/engine/SCons/Tool/tar.py
index 011f48b..83fb7d3 100644
--- a/src/engine/SCons/Tool/tar.py
+++ b/src/engine/SCons/Tool/tar.py
@@ -54,7 +54,7 @@ def generate(env):
         env['BUILDERS']['Tar'] = bld
 
     env['TAR']        = env.Detect(tars) or 'gtar'
-    env['TARFLAGS']   = '-c'
+    env['TARFLAGS']   = SCons.Util.CLVar('-c')
     env['TARCOM']     = '$TAR $TARFLAGS -f $TARGET $SOURCES'
     env['TARSUFFIX']  = '.tar'
 
diff --git a/src/engine/SCons/Tool/tex.py b/src/engine/SCons/Tool/tex.py
index c06efbf..b9257ea 100644
--- a/src/engine/SCons/Tool/tex.py
+++ b/src/engine/SCons/Tool/tex.py
@@ -101,16 +101,16 @@ def generate(env):
     bld.add_action('.tex', TeXLaTeXAction)
 
     env['TEX']      = 'tex'
-    env['TEXFLAGS'] = ''
+    env['TEXFLAGS'] = SCons.Util.CLVar('')
     env['TEXCOM']   = '$TEX $TEXFLAGS $SOURCES'
 
     # Duplicate from latex.py.  If latex.py goes away, then this is still OK.
     env['LATEX']      = 'latex'
-    env['LATEXFLAGS'] = ''
+    env['LATEXFLAGS'] = SCons.Util.CLVar('')
     env['LATEXCOM']   = '$LATEX $LATEXFLAGS $SOURCES'
 
     env['BIBTEX']      = 'bibtex'
-    env['BIBTEXFLAGS'] = ''
+    env['BIBTEXFLAGS'] = SCons.Util.CLVar('')
     env['BIBTEXCOM']   = '$BIBTEX $BIBTEXFLAGS $SOURCES'
 
 
diff --git a/src/engine/SCons/Tool/tlib.py b/src/engine/SCons/Tool/tlib.py
index 6ce1bf4..4a70c14 100644
--- a/src/engine/SCons/Tool/tlib.py
+++ b/src/engine/SCons/Tool/tlib.py
@@ -31,13 +31,14 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import SCons.Tool
 import SCons.Tool.bcc32
+import SCons.Util
 
 def generate(env):
     SCons.Tool.bcc32.findIt('tlib', env)
     """Add Builders and construction variables for ar to an Environment."""
     SCons.Tool.createStaticLibBuilder(env)
     env['AR']          = 'tlib'
-    env['ARFLAGS']     = ''
+    env['ARFLAGS']     = SCons.Util.CLVar('')
     env['ARCOM']       = '$AR $TARGET $ARFLAGS /a $SOURCES'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/yacc.py b/src/engine/SCons/Tool/yacc.py
index c0274ce..cf54b78 100644
--- a/src/engine/SCons/Tool/yacc.py
+++ b/src/engine/SCons/Tool/yacc.py
@@ -34,7 +34,6 @@ selection method.
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 import os.path
-import string
 
 import SCons.Tool
 import SCons.Util
@@ -43,7 +42,7 @@ def _yaccEmitter(target, source, env, ysuf, hsuf):
     # If -d is specified on the command line, yacc will emit a .h
     # or .hpp file as well as a .c or .cpp file, depending on whether
     # the input file is a .y or .yy, respectively.
-    if len(source) and '-d' in string.split(env.subst("$YACCFLAGS")):
+    if len(source) and '-d' in SCons.Util.CLVar(env.subst("$YACCFLAGS")):
         base, ext = os.path.splitext(SCons.Util.to_String(source[0]))
         if ext == ysuf:
             base, ext = os.path.splitext(SCons.Util.to_String(target[0]))
@@ -66,7 +65,7 @@ def generate(env):
     cxx_file.add_emitter('.yy', yyEmitter)
 
     env['YACC']      = env.Detect('bison') or 'yacc'
-    env['YACCFLAGS'] = ''
+    env['YACCFLAGS'] = SCons.Util.CLVar('')
     env['YACCCOM']   = '$YACC $YACCFLAGS -o $TARGET $SOURCES'
 
 def exists(env):
diff --git a/src/engine/SCons/Tool/zip.py b/src/engine/SCons/Tool/zip.py
index 18f0caa..c81a4f3 100644
--- a/src/engine/SCons/Tool/zip.py
+++ b/src/engine/SCons/Tool/zip.py
@@ -83,7 +83,7 @@ def generate(env):
         env['BUILDERS']['Zip'] = bld
 
     env['ZIP']        = 'zip'
-    env['ZIPFLAGS']   = ''
+    env['ZIPFLAGS']   = SCons.Util.CLVar('')
     env['ZIPCOM']     = zipAction
     env['ZIPCOMPRESSION'] =  zipcompression
     env['ZIPSUFFIX']  = '.zip'
diff --git a/src/engine/SCons/Util.py b/src/engine/SCons/Util.py
index 4ca25b2..2fb4e93 100644
--- a/src/engine/SCons/Util.py
+++ b/src/engine/SCons/Util.py
@@ -1202,6 +1202,33 @@ else:
 
 display = DisplayEngine()
 
+def Split(arg):
+    if is_List(arg):
+        return arg
+    elif is_String(arg):
+        return string.split(arg)
+    else:
+        return [arg]
+
+class CLVar(UserList.UserList):
+    """A class for command-line construction variables.
+
+    This is a list that uses Split() to split an initial string along
+    white-space arguments, and similarly to split any strings that get
+    added.  This allows us to Do the Right Thing with Append() and
+    Prepend() (as well as straight Python foo = env['VAR'] + 'arg1
+    arg2') regardless of whether a user adds a list or a string to a
+    command-line construction variable.
+    """
+    def __init__(self, seq = []):
+        UserList.UserList.__init__(self, Split(seq))
+    def __coerce__(self, other):
+        if is_String(other):
+            other = Split(other)
+        return (self, other)
+    def __str__(self):
+        return string.join(self.data)
+
 class Selector(UserDict.UserDict):
     """A callable dictionary that maps file suffixes to dictionary
     values."""
diff --git a/src/engine/SCons/UtilTests.py b/src/engine/SCons/UtilTests.py
index d981abc..8591119 100644
--- a/src/engine/SCons/UtilTests.py
+++ b/src/engine/SCons/UtilTests.py
@@ -1305,6 +1305,123 @@ class UtilTestCase(unittest.TestCase):
         assert nl[0:2].child.bar == [ 't1child', 't2child' ], \
                nl[0:2].child.bar
 
+    def test_CLVar(self):
+        """Test the command-line construction variable class"""
+        f = SCons.Util.CLVar('a b')
+
+        r = f + 'c d'
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', 'c', 'd'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + ' c d'
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', 'c', 'd'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + ['c d']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', 'c d'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + [' c d']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', ' c d'], r.data
+        assert str(r) == 'a b  c d', str(r)
+
+        r = f + ['c', 'd']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', 'c', 'd'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + [' c', 'd']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', ' c', 'd'], r.data
+        assert str(r) == 'a b  c d', str(r)
+
+        f = SCons.Util.CLVar(['a b'])
+
+        r = f + 'c d'
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a b', 'c', 'd'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + ' c d'
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a b', 'c', 'd'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + ['c d']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a b', 'c d'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + [' c d']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a b', ' c d'], r.data
+        assert str(r) == 'a b  c d', str(r)
+
+        r = f + ['c', 'd']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a b', 'c', 'd'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + [' c', 'd']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a b', ' c', 'd'], r.data
+        assert str(r) == 'a b  c d', str(r)
+
+        f = SCons.Util.CLVar(['a', 'b'])
+
+        r = f + 'c d'
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', 'c', 'd'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + ' c d'
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', 'c', 'd'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + ['c d']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', 'c d'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + [' c d']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', ' c d'], r.data
+        assert str(r) == 'a b  c d', str(r)
+
+        r = f + ['c', 'd']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', 'c', 'd'], r.data
+        assert str(r) == 'a b c d', str(r)
+
+        r = f + [' c', 'd']
+        assert isinstance(r, SCons.Util.CLVar), type(r)
+        assert r.data == ['a', 'b', ' c', 'd'], r.data
+        assert str(r) == 'a b  c d', str(r)
+
+        loc = {}
+        loc['FOO'] = 'foo'
+        loc['BAR'] = SCons.Util.CLVar('bar')
+        loc['CALL'] = lambda target, source, env, for_signature: 'call'
+        env = DummyEnv(loc)
+
+        cmd = SCons.Util.CLVar("test $FOO $BAR $CALL test")
+
+        newcmd = scons_subst(cmd, env)
+        assert newcmd == 'test foo bar call test', newcmd
+
+        cmd_list = scons_subst_list(cmd, env)
+        assert len(cmd_list) == 1, cmd_list
+        assert cmd_list[0][0] == "test", cmd_list[0][0]
+        assert cmd_list[0][1] == "foo", cmd_list[0][1]
+        assert cmd_list[0][2] == "bar", cmd_list[0][2]
+        assert cmd_list[0][3] == "call", cmd_list[0][3]
+        assert cmd_list[0][4] == "test", cmd_list[0][4]
+
     def test_Selector(self):
         """Test the Selector class"""