add support for a top-level __extension__ marker, implementing a todo.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@41004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Parse/Parser.cpp b/Parse/Parser.cpp
index 3a5885a..7ff0609 100644
--- a/Parse/Parser.cpp
+++ b/Parse/Parser.cpp
@@ -282,11 +282,11 @@
 
 /// ParseExternalDeclaration:
 ///       external-declaration: [C99 6.9]
-///         function-definition        [TODO]
-///         declaration                [TODO]
+///         function-definition
+///         declaration
 /// [EXT]   ';'
 /// [GNU]   asm-definition
-/// [GNU]   __extension__ external-declaration     [TODO]
+/// [GNU]   __extension__ external-declaration
 /// [OBJC]  objc-class-definition
 /// [OBJC]  objc-class-declaration
 /// [OBJC]  objc-alias-declaration
@@ -304,6 +304,13 @@
     ConsumeToken();
     // TODO: Invoke action for top-level semicolon.
     return 0;
+  case tok::kw___extension__: {
+    ConsumeToken();
+    // FIXME: Disable extension warnings.
+    DeclTy *RV = ParseExternalDeclaration();
+    // FIXME: Restore extension warnings.
+    return RV;
+  }
   case tok::kw_asm:
     ParseSimpleAsm();
     ExpectAndConsume(tok::semi, diag::err_expected_semi_after,