Patch #1608. Someone with access to autoconf 2.61 or higher needs to

run it and check in the resulting configure file.

Misc/ACKS

@@ -167,6 +167,7 @@ Yves Dionne
 Daniel Dittmar
 Walter Dörwald
 Jaromir Dolecek
+Ismail Donmez
 Dima Dorfman
 Cesar Douady
 Dean Draayer

Misc/NEWS

@@ -1123,6 +1123,10 @@ Tools/Demos
 Build
 -----
 
+- Bug #1608: use -fwrapv when GCC supports it.  This is important,
+  newer GCC versions may optimize away overflow buffer overflow checks
+  without this option!
+
 - Patch #1418: Make the AC_REPLACE_FUNCS object files actually work.
 
 - Add a FAST_LOOPS build option that speeds-up looping by trading away

configure.in

@@ -757,6 +757,10 @@ then
         if test "$CC" != 'g++' ; then
 	    STRICT_PROTO="-Wstrict-prototypes"
 	fi
+        # For gcc 4.x we need to use -fwrapv so lets check if its supported
+        if "$CC" -v --help 2>/dev/null |grep -- -fwrapv > /dev/null; then
+           WRAP="-fwrapv"
+        fi
 	case $ac_cv_prog_cc_g in
 	yes)
 	    if test "$Py_DEBUG" = 'true' ; then
@@ -764,7 +768,7 @@ then
 		# debug builds.
 		OPT="-g -Wall $STRICT_PROTO"
 	    else
-		OPT="-g -O3 -Wall $STRICT_PROTO"
+		OPT="-g $WRAP -O3 -Wall $STRICT_PROTO"
 	    fi
 	    ;;
 	*)