Silence warning -Wmissing-sysroot.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@309636 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit afae1deff64187e970ea9a87c411383bbddaf2ce)
diff --git a/test/Driver/darwin-version.c b/test/Driver/darwin-version.c
index a3e5fd8..73ed276 100644
--- a/test/Driver/darwin-version.c
+++ b/test/Driver/darwin-version.c
@@ -26,7 +26,7 @@
 
 // RUN: %clang -target armv7-apple-ios11.1 -c -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=CHECK-VERSION-IOS7 %s
-// RUN: %clang -arch armv7 -isysroot SDKs/iPhoneOS11.0.sdk -c -### %s 2>&1 | \
+// RUN: %clang -arch armv7 -Wno-missing-sysroot -isysroot SDKs/iPhoneOS11.0.sdk -c -### %s 2>&1 | \
 // RUN: FileCheck --check-prefix=CHECK-VERSION-IOS7 %s
 // CHECK-VERSION-IOS7: thumbv7-apple-ios10.99.99