Add comment to test linking it back to the original Bugzilla PR.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@94816 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Sema/format-string-percentm.c b/test/Sema/format-string-percentm.c
index f2e9dd8..1ffc439 100644
--- a/test/Sema/format-string-percentm.c
+++ b/test/Sema/format-string-percentm.c
@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s -triple i686-pc-linux-gnu
 
+// PR 4142 - support glibc extension to printf: '%m' (which prints strerror(errno)).
 int printf(char const*,...);
 void percentm(void) {
   printf("%m");