Add support for the __has_trivial_constructor type trait.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69245 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseExpr.cpp b/lib/Parse/ParseExpr.cpp
index 20a8359..d41586c 100644
--- a/lib/Parse/ParseExpr.cpp
+++ b/lib/Parse/ParseExpr.cpp
@@ -481,7 +481,7 @@
 ///                   '__has_nothrow_constructor'             [TODO]
 ///                   '__has_trivial_assign'                  [TODO]
 ///                   '__has_trivial_copy'                    [TODO]
-///                   '__has_trivial_constructor'             [TODO]
+///                   '__has_trivial_constructor'
 ///                   '__has_trivial_destructor'              [TODO]
 ///                   '__has_virtual_destructor'              [TODO]
 ///                   '__is_abstract'                         [TODO]
@@ -771,6 +771,7 @@
   case tok::kw___is_union:
   case tok::kw___is_polymorphic:
   case tok::kw___is_abstract:
+  case tok::kw___has_trivial_constructor:
     return ParseUnaryTypeTrait();
 
   case tok::at: {