[Serialization] Add missing includes for CHAR_BIT

clang/include/clang/Serialization/SourceLocationEncoding.h

@@ -26,6 +26,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include <climits>
 #include "clang/Basic/SourceLocation.h"
 
 #ifndef LLVM_CLANG_SERIALIZATION_SOURCELOCATIONENCODING_H

clang/unittests/Serialization/SourceLocationEncodingTest.cpp

@@ -9,6 +9,7 @@
 #include "clang/Serialization/SourceLocationEncoding.h"
 
 #include "gtest/gtest.h"
+#include <climits>
 
 using namespace llvm;
 using namespace clang;