--- configure.ac	2012-03-01 15:00:28.000000000 +0100
+++ configure.ac	2012-03-01 15:00:40.000000000 +0100
@@ -815,7 +815,7 @@
 dnl Report anything stripped as a flag in CFLAGS and 
 dnl only the compiler in CC_VERSION.
 CC_NOFLAGS=`echo $CC | sed 's/ -.*//'`
-CFLAGS_TO_ADD=`echo $CC | grep - | sed 's/.* -/-/'`
+CFLAGS_TO_ADD=`echo $CC | grep \ - | sed 's/.* -/-/'`
 if test -n $CFLAGS_TO_ADD; then
   CFLAGS="$CFLAGS_TO_ADD$CFLAGS"
 fi