Adapt to Clang 5 change of PPCallbacks::MacroUndefined signature

...since <http://llvm.org/viewvc/llvm-project?view=revision&revision=301449>
"PPCallbacks::MacroUndefined, change signature and add test."

Change-Id: I6a420dc4ca33607fef1356e8869cedee87192e93

compilerplugins/clang/checkconfigmacros.cxx

@@ -37,7 +37,11 @@ class CheckConfigMacros
         explicit CheckConfigMacros( const InstantiationData& data );
         virtual void run() override;
         virtual void MacroDefined( const Token& macroToken, const MacroDirective* info ) override;
-        virtual void MacroUndefined( const Token& macroToken, compat::MacroDefinitionParam ) override;
+        virtual void MacroUndefined( const Token& macroToken, compat::MacroDefinitionParam
+#if CLANG_VERSION >= 50000
+            , MacroDirective const *
+#endif
+            ) override;
         virtual void Ifdef( SourceLocation location, const Token& macroToken, compat::MacroDefinitionParam ) override;
         virtual void Ifndef( SourceLocation location, const Token& macroToken, compat::MacroDefinitionParam ) override;
         virtual void Defined( const Token& macroToken, compat::MacroDefinitionParam, SourceRange Range ) override;
@@ -71,7 +75,11 @@ void CheckConfigMacros::MacroDefined( const Token& macroToken, const MacroDirect
         }
     }
 
-void CheckConfigMacros::MacroUndefined( const Token& macroToken, compat::MacroDefinitionParam )
+void CheckConfigMacros::MacroUndefined( const Token& macroToken, compat::MacroDefinitionParam
+#if CLANG_VERSION >= 50000
+                                        , MacroDirective const *
+#endif
+                                        )
     {
     configMacros.erase( macroToken.getIdentifierInfo()->getName());
     }

compilerplugins/clang/oslendian.cxx

@@ -59,7 +59,11 @@ private:
     }
 
     void MacroUndefined(
-        Token const & MacroNameTok, compat::MacroDefinitionParam) override
+        Token const & MacroNameTok, compat::MacroDefinitionParam
+#if CLANG_VERSION >= 50000
+        , MacroDirective const *
+#endif
+        ) override
     {
         auto id = MacroNameTok.getIdentifierInfo()->getName();
         if (id == "OSL_BIGENDIAN" || id == "OSL_LITENDIAN") {