[modules] Fix a #include cycle when building a module for our builtin headers.

xmmintrin.h includes emmintrin.h and vice versa if SSE2 is enabled. We break
this cycle for a modules build, and instead make the xmmintrin.h module
re-export the immintrin.h module. Also included is a fix for an assert in the
serialization code if a module exports another module that was declared later
in the same module map.

llvm-svn: 237321

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/test/Headers/Inputs/include/stdlib.h b/clang/test/Headers/Inputs/include/stdlib.h
new file mode 100644
index 00000000000..296b6239f67
--- /dev/null
+++ b/clang/test/Headers/Inputs/include/stdlib.h
@@ -0,0 +1,2 @@
+#pragma once
+typedef __SIZE_TYPE__ size_t;