Merged scons/scons into default

6 files changed, 107 insertions, 165 deletions

diff --git a/src/engine/SCons/Script/Interactive.py b/src/engine/SCons/Script/Interactive.py
index ffb5096..e7a0658 100644
--- a/src/engine/SCons/Script/Interactive.py
+++ b/src/engine/SCons/Script/Interactive.py
@@ -19,6 +19,7 @@
 # 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.
+from __future__ import print_function
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
@@ -129,12 +130,12 @@ class SConsInteractiveCmd(cmd.Cmd):
             self.shell_variable = 'SHELL'
 
     def default(self, argv):
-        print "*** Unknown command: %s" % argv[0]
+        print("*** Unknown command: %s" % argv[0])
 
     def onecmd(self, line):
         line = line.strip()
         if not line:
-            print self.lastcmd
+            print(self.lastcmd)
             return self.emptyline()
         self.lastcmd = line
         if line[0] == '!':
@@ -274,7 +275,7 @@ class SConsInteractiveCmd(cmd.Cmd):
         return self.do_build(['build', '--clean'] + argv[1:])
 
     def do_EOF(self, argv):
-        print
+        print()
         self.do_exit(argv)
 
     def _do_one_help(self, arg):
@@ -304,14 +305,8 @@ class SConsInteractiveCmd(cmd.Cmd):
         return self._strip_initial_spaces(doc)
 
     def _strip_initial_spaces(self, s):
-        #lines = s.split('\n')
         lines = s.split('\n')
         spaces = re.match(' *', lines[0]).group(0)
-        #def strip_spaces(l):
-        #    if l.startswith(spaces):
-        #        l = l[len(spaces):]
-        #    return l
-        #return '\n'.join([ strip_spaces(l) for l in lines ])
         def strip_spaces(l, spaces=spaces):
             if l[:len(spaces)] == spaces:
                 l = l[len(spaces):]
@@ -357,7 +352,7 @@ class SConsInteractiveCmd(cmd.Cmd):
             # Doing the right thing with an argument list currently
             # requires different shell= values on Windows and Linux.
             p = subprocess.Popen(argv, shell=(sys.platform=='win32'))
-        except EnvironmentError, e:
+        except EnvironmentError as e:
             sys.stderr.write('scons: %s: %s\n' % (argv[0], e.strerror))
         else:
             p.wait()
diff --git a/src/engine/SCons/Script/Main.py b/src/engine/SCons/Script/Main.py
index 323fba9..c0b22a7 100644
--- a/src/engine/SCons/Script/Main.py
+++ b/src/engine/SCons/Script/Main.py
@@ -10,9 +10,13 @@ some other module.  If it's specific to the "scons" script invocation,
 it goes here.
 """
 
-unsupported_python_version = (2, 3, 0)
+from __future__ import print_function
+
+
+unsupported_python_version = (2, 6, 0)
 deprecated_python_version = (2, 7, 0)
 
+
 # __COPYRIGHT__
 #
 # Permission is hereby granted, free of charge, to any person obtaining
@@ -36,6 +40,7 @@ deprecated_python_version = (2, 7, 0)
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+
 import SCons.compat
 
 import os
@@ -43,15 +48,6 @@ import sys
 import time
 import traceback
 
-# Strip the script directory from sys.path() so on case-insensitive
-# (Windows) systems Python doesn't think that the "scons" script is the
-# "SCons" package.  Replace it with our own version directory so, if
-# if they're there, we pick up the right version of the build engine
-# modules.
-#sys.path = [os.path.join(sys.prefix,
-#                         'lib',
-#                         'scons-%d' % SCons.__version__)] + sys.path[1:]
-
 import SCons.CacheDir
 import SCons.Debug
 import SCons.Defaults
@@ -74,7 +70,7 @@ def fetch_win32_parallel_msg():
     # so we don't have to pull it in on all platforms, and so that an
     # in-line "import" statement in the _main() function below doesn't
     # cause warnings about local names shadowing use of the 'SCons'
-    # globl in nest scopes and UnboundLocalErrors and the like in some
+    # global in nest scopes and UnboundLocalErrors and the like in some
     # versions (2.1) of Python.
     import SCons.Platform.win32
     return SCons.Platform.win32.parallel_msg
@@ -229,7 +225,7 @@ class BuildTask(SCons.Taskmaster.OutOfDateTask):
                     self.exception_set()
                 self.do_failed()
             else:
-                print "scons: Nothing to be done for `%s'." % t
+                print("scons: Nothing to be done for `%s'." % t)
                 SCons.Taskmaster.OutOfDateTask.executed(self)
         else:
             SCons.Taskmaster.OutOfDateTask.executed(self)
@@ -298,8 +294,8 @@ class BuildTask(SCons.Taskmaster.OutOfDateTask):
             if self.options.debug_includes:
                 tree = t.render_include_tree()
                 if tree:
-                    print
-                    print tree
+                    print()
+                    print(tree)
         SCons.Taskmaster.OutOfDateTask.postprocess(self)
 
     def make_ready(self):
@@ -334,10 +330,10 @@ class CleanTask(SCons.Taskmaster.AlwaysTask):
                 else:
                     errstr = "Path '%s' exists but isn't a file or directory."
                     raise SCons.Errors.UserError(errstr % (pathstr))
-        except SCons.Errors.UserError, e:
-            print e
-        except (IOError, OSError), e:
-            print "scons: Could not remove '%s':" % pathstr, e.strerror
+        except SCons.Errors.UserError as e:
+            print(e)
+        except (IOError, OSError) as e:
+            print("scons: Could not remove '%s':" % pathstr, e.strerror)
 
     def _get_files_to_clean(self):
         result = []
@@ -363,13 +359,13 @@ class CleanTask(SCons.Taskmaster.AlwaysTask):
         for t in self._get_files_to_clean():
             try:
                 removed = t.remove()
-            except OSError, e:
+            except OSError as e:
                 # An OSError may indicate something like a permissions
                 # issue, an IOError would indicate something like
                 # the file not existing.  In either case, print a
                 # message and keep going to try to remove as many
-                # targets aa possible.
-                print "scons: Could not remove '%s':" % str(t), e.strerror
+                # targets as possible.
+                print("scons: Could not remove '{0}'".format(str(t)), e.strerror)
             else:
                 if removed:
                     display("Removed " + str(t))
@@ -383,7 +379,7 @@ class CleanTask(SCons.Taskmaster.AlwaysTask):
     # we don't want, like store .sconsign information.
     executed = SCons.Taskmaster.Task.executed_without_callbacks
 
-    # Have the taskmaster arrange to "execute" all of the targets, because
+    # Have the Taskmaster arrange to "execute" all of the targets, because
     # we'll figure out ourselves (in remove() or show() above) whether
     # anything really needs to be done.
     make_ready = SCons.Taskmaster.Task.make_ready_all
@@ -484,7 +480,9 @@ def GetOption(name):
 def SetOption(name, value):
     return OptionsParser.values.set_option(name, value)
 
-#
+def PrintHelp(file=None):
+    OptionsParser.print_help(file=file)
+
 class Stats(object):
     def __init__(self):
         self.stats = []
@@ -607,7 +605,7 @@ def _scons_internal_error():
     """Handle all errors but user errors. Print out a message telling
     the user what to do in this case and print a normal trace.
     """
-    print 'internal error'
+    print('internal error')
     traceback.print_exc()
     sys.exit(2)
 
@@ -708,7 +706,6 @@ def _load_site_scons_dir(topdir, site_dir_name=None):
     site_tools_dir = os.path.join(site_dir, site_tools_dirname)
     if os.path.exists(site_init_file):
         import imp, re
-        # TODO(2.4): turn this into try:-except:-finally:
         try:
             try:
                 fp, pathname, description = imp.find_module(site_init_modname,
@@ -722,7 +719,7 @@ def _load_site_scons_dir(topdir, site_dir_name=None):
                 # the error checking makes it longer.
                 try:
                     m = sys.modules['SCons.Script']
-                except Exception, e:
+                except Exception as e:
                     fmt = 'cannot import site_init.py: missing SCons.Script module %s'
                     raise SCons.Errors.InternalError(fmt % repr(e))
                 try:
@@ -735,10 +732,10 @@ def _load_site_scons_dir(topdir, site_dir_name=None):
                             site_m[k] = m.__dict__[k]
 
                     # This is the magic.
-                    exec fp in site_m
+                    exec(compile(fp.read(), fp.name, 'exec'), site_m)
                 except KeyboardInterrupt:
                     raise
-                except Exception, e:
+                except Exception as e:
                     fmt = '*** Error loading site_init file %s:\n'
                     sys.stderr.write(fmt % repr(site_init_file))
                     raise
@@ -748,7 +745,7 @@ def _load_site_scons_dir(topdir, site_dir_name=None):
                             m.__dict__[k] = site_m[k]
             except KeyboardInterrupt:
                 raise
-            except ImportError, e:
+            except ImportError as e:
                 fmt = '*** cannot import site init file %s:\n'
                 sys.stderr.write(fmt % repr(site_init_file))
                 raise
@@ -800,7 +797,7 @@ def _load_all_site_scons_dirs(topdir, verbose=None):
     dirs=sysdirs + [topdir]
     for d in dirs:
         if verbose:    # this is used by unit tests.
-            print "Loading site dir ", d
+            print("Loading site dir ", d)
         _load_site_scons_dir(d)
 
 def test_load_all_site_scons_dirs(d):
@@ -1000,7 +997,7 @@ def _main(parser):
     try:
         for script in scripts:
             SCons.Script._SConscript._SConscript(fs, script)
-    except SCons.Errors.StopError, e:
+    except SCons.Errors.StopError as e:
         # We had problems reading an SConscript file, such as it
         # couldn't be copied in to the VariantDir.  Since we're just
         # reading SConscript files and haven't started building
@@ -1021,7 +1018,7 @@ def _main(parser):
     # the SConscript file.
     #
     # We delay enabling the PythonVersionWarning class until here so that,
-    # if they explicity disabled it in either in the command line or in
+    # if they explicitly disabled it in either in the command line or in
     # $SCONSFLAGS, or in the SConscript file, then the search through
     # the list of deprecated warning classes will find that disabling
     # first and not issue the warning.
@@ -1061,8 +1058,8 @@ def _main(parser):
             # SConscript files.  Give them the options usage.
             raise SConsPrintHelpException
         else:
-            print help_text
-            print "Use scons -H for help about command-line options."
+            print(help_text)
+            print("Use scons -H for help about command-line options.")
         exit_status = 0
         return
 
@@ -1099,7 +1096,7 @@ def _main(parser):
         nodes = _build_targets(fs, options, targets, target_top)
         if not nodes:
             revert_io()
-            print 'Found nothing to build'
+            print('Found nothing to build')
             exit_status = 2
 
 def _build_targets(fs, options, targets, target_top):
@@ -1229,13 +1226,8 @@ def _build_targets(fs, options, targets, target_top):
         def order(dependencies):
             """Randomize the dependencies."""
             import random
-            # This is cribbed from the implementation of
-            # random.shuffle() in Python 2.X.
-            d = dependencies
-            for i in range(len(d)-1, 0, -1):
-                j = int(random.random() * (i+1))
-                d[i], d[j] = d[j], d[i]
-            return d
+            random.shuffle(dependencies)
+            return dependencies
     else:
         def order(dependencies):
             """Leave the order of dependencies alone."""
@@ -1313,18 +1305,6 @@ def _exec_main(parser, values):
         # compat layer imports "cProfile" for us if it's available.
         from profile import Profile
 
-        # Some versions of Python 2.4 shipped a profiler that had the
-        # wrong 'c_exception' entry in its dispatch table.  Make sure
-        # we have the right one.  (This may put an unnecessary entry
-        # in the table in earlier versions of Python, but its presence
-        # shouldn't hurt anything).
-        try:
-            dispatch = Profile.dispatch
-        except AttributeError:
-            pass
-        else:
-            dispatch['c_exception'] = Profile.trace_dispatch_return
-
         prof = Profile()
         try:
             prof.runcall(_main, parser)
@@ -1360,7 +1340,7 @@ def main():
     parts.append("__COPYRIGHT__")
     version = ''.join(parts)
 
-    import SConsOptions
+    from . import SConsOptions
     parser = SConsOptions.Parser(version)
     values = SConsOptions.SConsValues(parser.get_default_values())
 
@@ -1371,23 +1351,23 @@ def main():
             _exec_main(parser, values)
         finally:
             revert_io()
-    except SystemExit, s:
+    except SystemExit as s:
         if s:
             exit_status = s
     except KeyboardInterrupt:
         print("scons: Build interrupted.")
         sys.exit(2)
-    except SyntaxError, e:
+    except SyntaxError as e:
         _scons_syntax_error(e)
     except SCons.Errors.InternalError:
         _scons_internal_error()
-    except SCons.Errors.UserError, e:
+    except SCons.Errors.UserError as e:
         _scons_user_error(e)
     except SConsPrintHelpException:
         parser.print_help()
         exit_status = 0
-    except SCons.Errors.BuildError, e:
-        print e
+    except SCons.Errors.BuildError as e:
+        print(e)
         exit_status = e.exitstatus
     except:
         # An exception here is likely a builtin Python exception Python
@@ -1423,10 +1403,10 @@ def main():
             else:
                 ct = last_command_end - first_command_start
         scons_time = total_time - sconscript_time - ct
-        print "Total build time: %f seconds"%total_time
-        print "Total SConscript file execution time: %f seconds"%sconscript_time
-        print "Total SCons execution time: %f seconds"%scons_time
-        print "Total command execution time: %f seconds"%ct
+        print("Total build time: %f seconds"%total_time)
+        print("Total SConscript file execution time: %f seconds"%sconscript_time)
+        print("Total SCons execution time: %f seconds"%scons_time)
+        print("Total command execution time: %f seconds"%ct)
 
     sys.exit(exit_status)
 
diff --git a/src/engine/SCons/Script/SConsOptions.py b/src/engine/SCons/Script/SConsOptions.py
index 8ecc093..b2f2858 100644
--- a/src/engine/SCons/Script/SConsOptions.py
+++ b/src/engine/SCons/Script/SConsOptions.py
@@ -161,7 +161,7 @@ class SConsValues(optparse.Values):
         elif name == 'diskcheck':
             try:
                 value = diskcheck_convert(value)
-            except ValueError, v:
+            except ValueError as v:
                 raise SCons.Errors.UserError("Not a valid diskcheck value: %s"%v)
             if 'diskcheck' not in self.__dict__:
                 # No --diskcheck= option was specified on the command line.
@@ -268,7 +268,7 @@ class SConsOptionParser(optparse.OptionParser):
     preserve_unknown_options = False
 
     def error(self, msg):
-        # overriden OptionValueError exception handler
+        # overridden OptionValueError exception handler
         self.print_usage(sys.stderr)
         sys.stderr.write("SCons Error: %s\n" % msg)
         sys.exit(2)
@@ -426,7 +426,7 @@ class SConsOptionParser(optparse.OptionParser):
         result = group.add_option(*args, **kw)
 
         if result:
-            # The option was added succesfully.  We now have to add the
+            # The option was added successfully.  We now have to add the
             # default value to our object that holds the default values
             # (so that an attempt to fetch the option's attribute will
             # yield the default value when not overridden) and then
@@ -449,11 +449,6 @@ class SConsIndentedHelpFormatter(optparse.IndentedHelpFormatter):
         "SCons Options."  Unfortunately, we have to do this here,
         because those titles are hard-coded in the optparse calls.
         """
-        if heading == 'options':
-            # The versions of optparse.py shipped with Pythons 2.3 and
-            # 2.4 pass this in uncapitalized; override that so we get
-            # consistent output on all versions.
-            heading = "Options"
         if heading == 'Options':
             heading = "SCons Options"
         return optparse.IndentedHelpFormatter.format_heading(self, heading)
@@ -488,13 +483,7 @@ class SConsIndentedHelpFormatter(optparse.IndentedHelpFormatter):
         #           read data from FILENAME
         result = []
 
-        try:
-            opts = self.option_strings[option]
-        except AttributeError:
-            # The Python 2.3 version of optparse attaches this to
-            # to the option argument, not to this object.
-            opts = option.option_strings
-
+        opts = self.option_strings[option]
         opt_width = self.help_position - self.current_indent - 2
         if len(opts) > opt_width:
             wrapper = textwrap.TextWrapper(width=self.width,
@@ -509,14 +498,7 @@ class SConsIndentedHelpFormatter(optparse.IndentedHelpFormatter):
         result.append(opts)
         if option.help:
 
-            try:
-                expand_default = self.expand_default
-            except AttributeError:
-                # The HelpFormatter base class in the Python 2.3 version
-                # of optparse has no expand_default() method.
-                help_text = option.help
-            else:
-                help_text = expand_default(option)
+            help_text = self.expand_default(option)
 
             # SCons:  indent every line of the help text but the first.
             wrapper = textwrap.TextWrapper(width=self.help_width,
@@ -530,34 +512,6 @@ class SConsIndentedHelpFormatter(optparse.IndentedHelpFormatter):
             result.append("\n")
         return "".join(result)
 
-    # For consistent help output across Python versions, we provide a
-    # subclass copy of format_option_strings() and these two variables.
-    # This is necessary (?) for Python2.3, which otherwise concatenates
-    # a short option with its metavar.
-    _short_opt_fmt = "%s %s"
-    _long_opt_fmt = "%s=%s"
-
-    def format_option_strings(self, option):
-        """Return a comma-separated list of option strings & metavariables."""
-        if option.takes_value():
-            metavar = option.metavar or option.dest.upper()
-            short_opts = []
-            for sopt in option._short_opts:
-                short_opts.append(self._short_opt_fmt % (sopt, metavar))
-            long_opts = []
-            for lopt in option._long_opts:
-                long_opts.append(self._long_opt_fmt % (lopt, metavar))
-        else:
-            short_opts = option._short_opts
-            long_opts = option._long_opts
-
-        if self.short_first:
-            opts = short_opts + long_opts
-        else:
-            opts = long_opts + short_opts
-
-        return ", ".join(opts)
-
 def Parser(version):
     """
     Returns an options parser object initialized with the standard
@@ -709,7 +663,7 @@ def Parser(version):
     def opt_diskcheck(option, opt, value, parser):
         try:
             diskcheck_value = diskcheck_convert(value)
-        except ValueError, e:
+        except ValueError as e:
             raise OptionValueError("`%s' is not a valid diskcheck type" % e)
         setattr(parser.values, option.dest, diskcheck_value)
 
@@ -876,7 +830,7 @@ def Parser(version):
     tree_options = ["all", "derived", "prune", "status"]
 
     def opt_tree(option, opt, value, parser, tree_options=tree_options):
-        import Main
+        from . import Main
         tp = Main.TreePrinter()
         for o in value.split(','):
             if o == 'all':
diff --git a/src/engine/SCons/Script/SConscript.py b/src/engine/SCons/Script/SConscript.py
index 0a5720d..6480ace 100644
--- a/src/engine/SCons/Script/SConscript.py
+++ b/src/engine/SCons/Script/SConscript.py
@@ -5,6 +5,8 @@ files.
 
 """
 
+from __future__ import print_function
+
 #
 # __COPYRIGHT__
 #
@@ -26,7 +28,6 @@ files.
 # 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.
-from __future__ import division
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
@@ -52,16 +53,6 @@ import re
 import sys
 import traceback
 
-# The following variables used to live in this module.  Some
-# SConscript files out there may have referred to them directly as
-# SCons.Script.SConscript.*.  This is now supported by some special
-# handling towards the bottom of the SConscript.__init__.py module.
-#Arguments = {}
-#ArgList = []
-#BuildTargets = TargetList()
-#CommandLineTargets = []
-#DefaultTargets = []
-
 class SConscriptReturn(Exception):
     pass
 
@@ -79,7 +70,7 @@ def get_calling_namespaces():
     """Return the locals and globals for the function that called
     into this module in the current call stack."""
     try: 1//0
-    except ZeroDivisionError: 
+    except ZeroDivisionError:
         # Don't start iterating with the current stack-frame to
         # prevent creating reference cycles (f_back is safe).
         frame = sys.exc_info()[2].tb_frame.f_back
@@ -113,7 +104,7 @@ def compute_exports(exports):
                     retval[export] = loc[export]
                 except KeyError:
                     retval[export] = glob[export]
-    except KeyError, x:
+    except KeyError as x:
         raise SCons.Errors.UserError("Export of non-existent variable '%s'"%x)
 
     return retval
@@ -145,7 +136,7 @@ def Return(*vars, **kw):
         for var in fvars:
             for v in var.split():
                 retval.append(call_stack[-1].globals[v])
-    except KeyError, x:
+    except KeyError as x:
         raise SCons.Errors.UserError("Return of non-existent variable '%s'"%x)
 
     if len(retval) == 1:
@@ -174,7 +165,7 @@ def _SConscript(fs, *files, **kw):
         try:
             SCons.Script.sconscript_reading = SCons.Script.sconscript_reading + 1
             if fn == "-":
-                exec sys.stdin in call_stack[-1].globals
+                exec(sys.stdin, call_stack[-1].globals)
             else:
                 if isinstance(fn, SCons.Node.Node):
                     f = fn
@@ -257,7 +248,8 @@ def _SConscript(fs, *files, **kw):
                         pass
                     try:
                         try:
-                            exec _file_ in call_stack[-1].globals
+                            exec(compile(_file_.read(), _file_.name, 'exec'),
+                                 call_stack[-1].globals)
                         except SConscriptReturn:
                             pass
                     finally:
@@ -282,7 +274,7 @@ def _SConscript(fs, *files, **kw):
                 rdir._create()  # Make sure there's a directory there.
                 try:
                     os.chdir(rdir.get_abspath())
-                except OSError, e:
+                except OSError as e:
                     # We still couldn't chdir there, so raise the error,
                     # but only if actions are being executed.
                     #
@@ -446,7 +438,7 @@ class SConsEnvironment(SCons.Environment.Base):
 
     #
     # Public methods of an SConsEnvironment.  These get
-    # entry points in the global name space so they can be called
+    # entry points in the global namespace so they can be called
     # as global functions.
     #
 
@@ -472,15 +464,15 @@ class SConsEnvironment(SCons.Environment.Base):
                 scons_ver_string = '%d.%d.%d' % (major, minor, revision)
             else:
                 scons_ver_string = '%d.%d' % (major, minor)
-            print "SCons %s or greater required, but you have SCons %s" % \
-                  (scons_ver_string, SCons.__version__)
+            print("SCons %s or greater required, but you have SCons %s" % \
+                  (scons_ver_string, SCons.__version__))
             sys.exit(2)
 
     def EnsurePythonVersion(self, major, minor):
         """Exit abnormally if the Python version is not late enough."""
         if sys.version_info < (major, minor):
             v = sys.version.split()[0]
-            print "Python %d.%d or greater required, but you have Python %s" %(major,minor,v)
+            print("Python %d.%d or greater required, but you have Python %s" %(major,minor,v))
             sys.exit(2)
 
     def Exit(self, value=0):
@@ -499,9 +491,9 @@ class SConsEnvironment(SCons.Environment.Base):
         name = self.subst(name)
         return SCons.Script.Main.GetOption(name)
 
-    def Help(self, text):
+    def Help(self, text, append=False):
         text = self.subst(text, raw=1)
-        SCons.Script.HelpFunction(text)
+        SCons.Script.HelpFunction(text, append=append)
 
     def Import(self, *vars):
         try:
@@ -519,7 +511,7 @@ class SConsEnvironment(SCons.Environment.Base):
                             globals[v] = exports[v]
                         else:
                             globals[v] = global_exports[v]
-        except KeyError,x:
+        except KeyError as x:
             raise SCons.Errors.UserError("Import of non-existent variable '%s'"%x)
 
     def SConscript(self, *ls, **kw):
diff --git a/src/engine/SCons/Script/SConscript.xml b/src/engine/SCons/Script/SConscript.xml
index c74ad5e..8553fbe 100644
--- a/src/engine/SCons/Script/SConscript.xml
+++ b/src/engine/SCons/Script/SConscript.xml
@@ -240,7 +240,7 @@ file is found.
 
 <scons_function name="Help">
 <arguments>
-(text)
+(text, append=False)
 </arguments>
 <summary>
 <para>
@@ -248,12 +248,18 @@ This specifies help text to be printed if the
 <option>-h</option>
 argument is given to
 &scons;.
-If
+If 
 &f-Help;
-is called multiple times, the text is appended together in the order
-that
+is called multiple times, the text is appended together in the order that 
 &f-Help;
-is called.
+is called. With append set to False, any 
+&f-Help;
+text generated with 
+&f-AddOption;
+is clobbered. If append is True, the AddOption help is prepended to the help
+string, thus preserving the 
+<option>-h</option>
+message.
 </para>
 </summary>
 </scons_function>
diff --git a/src/engine/SCons/Script/__init__.py b/src/engine/SCons/Script/__init__.py
index 90b1fc3..3fa3a48 100644
--- a/src/engine/SCons/Script/__init__.py
+++ b/src/engine/SCons/Script/__init__.py
@@ -41,6 +41,12 @@ start_time = time.time()
 
 import collections
 import os
+
+try:
+    from StringIO import StringIO
+except ImportError:
+    from io import StringIO
+
 import sys
 
 # Special chicken-and-egg handling of the "--debug=memoizer" flag:
@@ -66,7 +72,7 @@ if "--debug=memoizer" in _args:
     except SCons.Warnings.Warning:
         # Some warning was thrown.  Arrange for it to be displayed
         # or not after warnings are configured.
-        import Main
+        from . import Main
         exc_type, exc_value, tb = sys.exc_info()
         Main.delayed_warnings.append((exc_type, exc_value))
 del _args
@@ -85,7 +91,7 @@ import SCons.Util
 import SCons.Variables
 import SCons.Defaults
 
-import Main
+from . import Main
 
 main                    = Main.main
 
@@ -107,6 +113,7 @@ QuestionTask            = Main.QuestionTask
 #SConscriptSettableOptions = Main.SConscriptSettableOptions
 
 AddOption               = Main.AddOption
+PrintHelp               = Main.PrintHelp
 GetOption               = Main.GetOption
 SetOption               = Main.SetOption
 Progress                = Main.Progress
@@ -128,7 +135,7 @@ GetBuildFailures        = Main.GetBuildFailures
 #repositories            = Main.repositories
 
 #
-import SConscript
+from . import SConscript
 _SConscript = SConscript
 
 call_stack              = _SConscript.call_stack
@@ -258,12 +265,19 @@ def _Set_Default_Targets(env, tlist):
 #
 help_text = None
 
-def HelpFunction(text):
+def HelpFunction(text, append=False):
     global help_text
-    if SCons.Script.help_text is None:
-        SCons.Script.help_text = text
-    else:
-        help_text = help_text + text
+    if help_text is None:
+        if append:
+            s = StringIO()
+            PrintHelp(s)  
+            help_text = s.getvalue()
+            s.close()
+        else:
+            help_text = ""
+
+    help_text= help_text + text
+
 
 #
 # Will be non-zero if we are reading an SConscript file.
@@ -345,6 +359,7 @@ GlobalDefaultBuilders = [
     'Java',
     'JavaH',
     'Library',
+    'LoadableModule',
     'M4',
     'MSVSProject',
     'Object',
@@ -365,7 +380,7 @@ GlobalDefaultBuilders = [
 ]
 
 for name in GlobalDefaultEnvironmentFunctions + GlobalDefaultBuilders:
-    exec "%s = _SConscript.DefaultEnvironmentCall(%s)" % (name, repr(name))
+    exec ("%s = _SConscript.DefaultEnvironmentCall(%s)" % (name, repr(name)))
 del name
 
 # There are a handful of variables that used to live in the