Sort all of Clang's files under 'lib', and fix up the broken headers
uncovered.

This required manually correcting all of the incorrect main-module
headers I could find, and running the new llvm/utils/sort_includes.py
script over the files.

I also manually added quite a few missing headers that were uncovered by
shuffling the order or moving headers up to be main-module-headers.

llvm-svn: 169237
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 206f74a..76b98af 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -12,19 +12,19 @@
 //===----------------------------------------------------------------------===//
 
 #include "CodeGenFunction.h"
-#include "CodeGenModule.h"
 #include "CGCXXABI.h"
 #include "CGObjCRuntime.h"
 #include "CGRecordLayout.h"
+#include "CodeGenModule.h"
 #include "clang/AST/APValue.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/RecordLayout.h"
 #include "clang/AST/StmtVisitor.h"
 #include "clang/Basic/Builtins.h"
 #include "llvm/Constants.h"
+#include "llvm/DataLayout.h"
 #include "llvm/Function.h"
 #include "llvm/GlobalVariable.h"
-#include "llvm/DataLayout.h"
 using namespace clang;
 using namespace CodeGen;