clang/test/Driver/fsanitize-blacklist.c: Mark it as XFAIL:cygming, due to PR12920.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169180 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Driver/fsanitize-blacklist.c b/test/Driver/fsanitize-blacklist.c
index 5616522..353587b 100644
--- a/test/Driver/fsanitize-blacklist.c
+++ b/test/Driver/fsanitize-blacklist.c
@@ -13,3 +13,6 @@
 // Driver barks on unexisting blacklist files.
 // RUN: %clang -fno-sanitize-blacklist -fsanitize-blacklist=unexisting.txt %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-SUCH-FILE
 // CHECK-NO-SUCH-FILE: error: no such file or directory: 'unexisting.txt'
+
+// PR12920
+// XFAIL: cygwin,mingw32