more extreme gcc --version parsing

Change-Id: I5bb195e54274d9210ae8d4c2d31690ce8e79a425

configure.ac

@@ -2929,7 +2929,7 @@ dnl  Test the gcc version
 dnl ===================================================================
 if test "$GCC" = "yes"; then
     AC_MSG_CHECKING([the GCC version])
-    _gcc_version=`$CC --version|head -n1|sed -e 's/^.* //g' -e 's/-[[0-9]]*)$//'`
+    _gcc_version=$($CC --version|head -n1|sed -e 's/^.*[^[:digit:]]\(\([[:digit:]]\+\.\)\{2\}[[:digit:]]\+\).*/\1/')
     _gcc_major=`echo $_gcc_version | $AWK -F. '{ print \$1 }'`
     GCCVER=`echo $_gcc_version | $AWK -F. '{ print \$1*10000+\$2*100+\$3 }'`