Add test for -Wno-everything.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149123 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Frontend/Wno-everything.c b/test/Frontend/Wno-everything.c
new file mode 100644
index 0000000..ca70ca4
--- /dev/null
+++ b/test/Frontend/Wno-everything.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -verify -Wno-everything -Wsign-compare %s
+
+int f0(int, unsigned);
+int f0(int x, unsigned y) {
+  if (x=3);
+  return x < y; // expected-warning {{comparison of integers}}
+}