backport bug 17547 from http://hg.python.org/cpython/rev/9d50af4c482f/

-Wformat is needed by gcc 4.8

Signed-off-by: Khem Raj <raj.khem@gmail.com>

Upstream-Status: Backport
Index: Python-2.7.3/configure.in
===================================================================
--- Python-2.7.3.orig/configure.in	2013-06-11 02:22:04.186529212 -0700
+++ Python-2.7.3/configure.in	2013-06-13 02:17:06.324403327 -0700
@@ -1196,7 +1196,7 @@
 then
   AC_MSG_CHECKING(whether gcc supports ParseTuple __format__)
   save_CFLAGS=$CFLAGS
-  CFLAGS="$CFLAGS -Werror"
+  CFLAGS="$CFLAGS -Werror -Wformat"
   AC_COMPILE_IFELSE([
     AC_LANG_PROGRAM([[void f(char*,...)__attribute((format(PyArg_ParseTuple, 1, 2)));]], [[]])
   ],[