Add all of the C99 complex builtins prefixed with __builtin_

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@83020 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 48d1ce9..e0223b0 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -4118,6 +4118,11 @@
     Type = Context.getVectorType(ElementType, NumElements);
     break;
   }
+  case 'X': {
+    QualType ElementType = DecodeTypeFromStr(Str, Context, Error, false);
+    Type = Context.getComplexType(ElementType);
+    break;
+  }      
   case 'P':
     Type = Context.getFILEType();
     if (Type.isNull()) {