Initial implementation of -modules-earch-all option, for searching for symbols in non-imported modules.

llvm-svn: 206977
diff --git a/clang/unittests/Lex/PPCallbacksTest.cpp b/clang/unittests/Lex/PPCallbacksTest.cpp
index e3a4a76..3c953c2 100644
--- a/clang/unittests/Lex/PPCallbacksTest.cpp
+++ b/clang/unittests/Lex/PPCallbacksTest.cpp
@@ -45,6 +45,9 @@
                                  Module::NameVisibilityKind Visibility,
                                  SourceLocation ImportLoc,
                                  bool Complain) { }
+
+  virtual GlobalModuleIndex *loadGlobalModuleIndex(SourceLocation TriggerLoc)
+    { return 0; }
 };
 
 // Stub to collect data from InclusionDirective callbacks.