[Modules] Don't parse any module map if modules are disabled.

Fixes rdar://15644663.

llvm-svn: 197165
diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 9e43dda..5770aaa 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -59,6 +59,8 @@
   NumIncluded = 0;
   NumMultiIncludeFileOptzn = 0;
   NumFrameworkLookups = NumSubFrameworkLookups = 0;
+
+  EnabledModules = LangOpts.Modules;
 }
 
 HeaderSearch::~HeaderSearch() {
@@ -953,6 +955,9 @@
 bool HeaderSearch::hasModuleMap(StringRef FileName, 
                                 const DirectoryEntry *Root,
                                 bool IsSystem) {
+  if (!enabledModules())
+    return false;
+
   SmallVector<const DirectoryEntry *, 2> FixUpDirectories;
   
   StringRef DirName = FileName;