Additional safety for the root cause of regression in r223443; make the module
map path more canonical before hashing it. No functionality change.

llvm-svn: 223547
diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 131f6aa..bbbcf3a 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -137,6 +137,7 @@
     // error if they are imported in the same translation.
     SmallString<256> AbsModuleMapPath(ModuleMapPath);
     llvm::sys::fs::make_absolute(AbsModuleMapPath);
+    llvm::sys::path::native(AbsModuleMapPath);
     llvm::APInt Code(64, llvm::hash_value(AbsModuleMapPath.str().lower()));
     SmallString<128> HashStr;
     Code.toStringUnsigned(HashStr, /*Radix*/36);