Fix interaction of max_align_t and modules.
When building with modules enabled, we were defining max_align_t as a typedef
for a different anonymous struct type each time it was included, resulting in
an error if <stddef.h> is not covered by a module map and is included more than
once in the same modules-enabled compilation of C11 or C++11 code.
llvm-svn: 218931
diff --git a/clang/test/Modules/Inputs/StdDef/include_again.h b/clang/test/Modules/Inputs/StdDef/include_again.h
new file mode 100644
index 0000000..f29f636
--- /dev/null
+++ b/clang/test/Modules/Inputs/StdDef/include_again.h
@@ -0,0 +1,2 @@
+#include <stddef.h>
+