Only ignore extra tokens after #else if we skip it, otherwise warn. Fixes rdar://9475098.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131788 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPDirectives.cpp b/lib/Lex/PPDirectives.cpp
index af3fa6e..66e44bb 100644
--- a/lib/Lex/PPDirectives.cpp
+++ b/lib/Lex/PPDirectives.cpp
@@ -323,7 +323,6 @@
         // #else directive in a skipping conditional.  If not in some other
         // skipping conditional, and if #else hasn't already been seen, enter it
         // as a non-skipping conditional.
-        DiscardUntilEndOfDirective();  // C99 6.10p4.
         PPConditionalInfo &CondInfo = CurPPLexer->peekConditionalLevel();
 
         // If this is a #else with a #else before it, report the error.
@@ -339,7 +338,10 @@
         // entered, enter the #else block now.
         if (!CondInfo.WasSkipping && !CondInfo.FoundNonSkip) {
           CondInfo.FoundNonSkip = true;
+          CheckEndOfDirective("else");
           break;
+        } else {
+          DiscardUntilEndOfDirective();  // C99 6.10p4.
         }
       } else if (Sub == "lif") {  // "elif".
         PPConditionalInfo &CondInfo = CurPPLexer->peekConditionalLevel();