[WIP] customizable tempfile extension (issue #2431)

Apply the patch (adjusted) from issue #2341: instead of hardcoding
the filename extenstion for the tempfile to help with linking
on Windows targets, allow some variability.

Current marked WIP because there are some other comments in
the issue tracker that can maybe be flushed out by submitting
this PR, and there are no tests (should presumably go in
test/TEMPFILEPREFIX.py, or a new test TEMPFILEEXTENSION.py)

Signed-off-by: Mats Wichmann <mats@linux.com>

2 files changed, 25 insertions, 12 deletions

diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index 2c0cef6..8059f5d 100644
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -14,6 +14,8 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
     - Improve finding of Microsoft compiler: add a 'products' wildcard
       in case 2017 Build Tools only is installed as it is considered a separate
       product from the default Visual Studio
+    - Add TEMPFILEEXTENSION as in the patch attached to issue #2431,
+      updated to current codebase.
 
   From Daniel Moody:
     - Improved support for VC14.1 and Visual Studio 2017, as well as arm and arm64 targets.
diff --git a/src/engine/SCons/Platform/__init__.py b/src/engine/SCons/Platform/__init__.py
index 8117e60..75c4839 100644
--- a/src/engine/SCons/Platform/__init__.py
+++ b/src/engine/SCons/Platform/__init__.py
@@ -144,15 +144,20 @@ class TempFileMunge(object):
     line limitation.
 
     Example usage:
-    env["TEMPFILE"] = TempFileMunge
-    env["LINKCOM"] = "${TEMPFILE('$LINK $TARGET $SOURCES','$LINKCOMSTR')}"
+        env["TEMPFILE"] = TempFileMunge
+        env["LINKCOM"] = "${TEMPFILE('$LINK $TARGET $SOURCES','$LINKCOMSTR')}"
 
     By default, the name of the temporary file used begins with a
-    prefix of '@'.  This may be configred for other tool chains by
-    setting '$TEMPFILEPREFIX'.
-
-    env["TEMPFILEPREFIX"] = '-@'        # diab compiler
-    env["TEMPFILEPREFIX"] = '-via'      # arm tool chain
+    prefix of '@'.  This may be configured for other tool chains by
+    setting '$TEMPFILEPREFIX':
+        env["TEMPFILEPREFIX"] = '-@'        # diab compiler
+        env["TEMPFILEPREFIX"] = '-via'      # arm tool chain
+        env["TEMPFILEPREFIX"] = ''          # (the empty string) PC Lint
+
+    You can configure the extension of the temporary file through the
+    TEMPFILEEXTENSION variable, which defaults to '.lnk' (see comments
+    in the code below):
+        env["TEMPFILEEXTENSION"] = '.lnt'   # PC Lint
     """
     def __init__(self, cmd, cmdstr = None):
         self.cmd = cmd
@@ -194,16 +199,21 @@ class TempFileMunge(object):
 
         # We do a normpath because mktemp() has what appears to be
         # a bug in Windows that will use a forward slash as a path
-        # delimiter.  Windows's link mistakes that for a command line
+        # delimiter.  Windows' link mistakes that for a command line
         # switch and barfs.
         #
         # We use the .lnk suffix for the benefit of the Phar Lap
         # linkloc linker, which likes to append an .lnk suffix if
         # none is given.
-        (fd, tmp) = tempfile.mkstemp('.lnk', text=True)
+        if env.has_key('TEMPFILEEXTENSION'):
+            extension = env.subst('$TEMPFILEEXTENSION')
+        else:
+            extension = '.lnk'  # TODO: better way to pick default?
+        (fd, tmp) = tempfile.mkstemp(extension, text=True)
+
         native_tmp = SCons.Util.get_native_path(os.path.normpath(tmp))
 
-        if env.get('SHELL',None) == 'sh':
+        if env.get('SHELL', None) == 'sh':
             # The sh shell will try to escape the backslashes in the
             # path, so unescape them.
             native_tmp = native_tmp.replace('\\', r'\\\\')
@@ -216,8 +226,9 @@ class TempFileMunge(object):
             # Windows path names.
             rm = 'del'
 
-        prefix = env.subst('$TEMPFILEPREFIX')
-        if not prefix:
+        if env.has_key('TEMPFILEPREFIX'):
+            prefix = env.subst('$TEMPFILEPREFIX')
+        else:
             prefix = '@'
 
         args = list(map(SCons.Subst.quote_spaces, cmd[1:]))