Improve diagnostics from the assembler __memset_chk routines.

Change-Id: Ic165043ab8cd5e16866b3e11cfba960514cbdc57
diff --git a/tests/fortify_test.cpp b/tests/fortify_test.cpp
index 4ffd5f9..e1ff769 100644
--- a/tests/fortify_test.cpp
+++ b/tests/fortify_test.cpp
@@ -560,6 +560,12 @@
   ASSERT_FORTIFY(memcpy(bufb, bufa, n));
 }
 
+TEST_F(DEATHTEST, memset_fortified) {
+  char buf[10];
+  size_t n = atoi("11");
+  ASSERT_FORTIFY(memset(buf, 0, n));
+}
+
 TEST_F(DEATHTEST, stpncpy_fortified) {
   char bufa[15];
   char bufb[10];