Try to fix Win32 failures

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169923 91177308-0d34-0410-b5e6-96231b3b80d8

test/PCH/modified-header-crash.c

@@ -2,7 +2,7 @@
 
 // RUN: cp %S/modified-header-crash.h %t.h
 // RUN: %clang_cc1 -DCAKE -x c-header %t.h -emit-pch -o %t
-// RUN: echo >> %t.h
+// RUN: echo 'int foobar;' >> %t.h
 // RUN: not %clang_cc1 %s -include-pch %t -fsyntax-only
 
 void f(void) {