Detect latest FC12 gcc -combine breakage.

Now, assigning a value to a global is needed to triger ICE.
diff --git a/tools/test-gcc.sh b/tools/test-gcc.sh
index 3bb91e9..ce3497b 100755
--- a/tools/test-gcc.sh
+++ b/tools/test-gcc.sh
@@ -55,6 +55,7 @@
 struct s1_s { int v; } g1;
 void __attribute__((externally_visible)) func2() {
     struct s1_s *l1 = &g1;
+    l1->v=0;
 }
 EOF
 cat - > $TMPFILE2 <<EOF