Introduced EXTRA_CFLAGS as an environment variable used by the Makefile.  Meant
to be used for flags that change binary compatibility.

Distutils was tweaked to also use the variable if used during compilation of
the interpreter.
diff --git a/Lib/distutils/sysconfig.py b/Lib/distutils/sysconfig.py
index aae0f27..1bd6209 100644
--- a/Lib/distutils/sysconfig.py
+++ b/Lib/distutils/sysconfig.py
@@ -146,8 +146,9 @@
     varies across Unices and is stored in Python's Makefile.
     """
     if compiler.compiler_type == "unix":
-        (cc, cxx, opt, basecflags, ccshared, ldshared, so_ext) = \
-            get_config_vars('CC', 'CXX', 'OPT', 'BASECFLAGS', 'CCSHARED', 'LDSHARED', 'SO')
+        (cc, cxx, opt, extra_cflags, basecflags, ccshared, ldshared, so_ext) = \
+            get_config_vars('CC', 'CXX', 'OPT', 'EXTRA_CFLAGS', 'BASECFLAGS',
+                            'CCSHARED', 'LDSHARED', 'SO')
 
         if os.environ.has_key('CC'):
             cc = os.environ['CC']
@@ -171,7 +172,7 @@
             opt = opt + ' ' + os.environ['CPPFLAGS']
             ldshared = ldshared + ' ' + os.environ['CPPFLAGS']
 
-        cc_cmd = cc + ' ' + opt
+        cc_cmd = ' '.join(str(x) for x in (cc, opt, extra_cflags) if x)
         compiler.set_executables(
             preprocessor=cpp,
             compiler=cc_cmd,