backup Makefile too

diff --git a/Tools/freeze/freeze.py b/Tools/freeze/freeze.py
index e3c2dddef9084e34ee024a8b42192368d3cca48d..d4e4b051374fe41d8413cb4327aa06d8db04fd22 100755 (executable)
--- a/Tools/freeze/freeze.py
+++ b/Tools/freeze/freeze.py
@@ -19,7 +19,7 @@ usage: freeze [-p prefix] [-e extension] ... script [module] ...
 -p prefix:    This is the prefix used when you ran
               'Make inclinstall libainstall' in the Python build directory.
               (If you never ran this, freeze won't work.)
-               The default is /usr/local.
+              The default is /usr/local.
 
 -e extension: A directory containing additional .o files that
               may be used to resolve modules.  This directory
@@ -227,11 +227,23 @@ def main():
                addfiles + libs + \
                ['$(MODLIBS)', '$(LIBS)', '$(SYSLIBS)']
 
+       backup = makefile + '~'
+       try:
+               os.rename(makefile, backup)
+       except os.error:
+               backup = None
        outfp = open(makefile, 'w')
        try:
                makemakefile.makemakefile(outfp, somevars, files, target)
        finally:
                outfp.close()
+       if backup:
+               if not cmp.cmp(backup, makefile):
+                       print 'previous Makefile saved as', backup
+               else:
+                       sys.stderr.write('%s not changed, not written\n' %
+                                        makefile)
+                       os.rename(backup, makefile)
 
        # Done!