Registering the gnuNullExpr AST matcher as a dynamic matcher so that it is available from clang-query.

llvm-svn: 260222
diff --git a/clang/lib/ASTMatchers/Dynamic/Registry.cpp b/clang/lib/ASTMatchers/Dynamic/Registry.cpp
index df4f29d..8948d18 100644
--- a/clang/lib/ASTMatchers/Dynamic/Registry.cpp
+++ b/clang/lib/ASTMatchers/Dynamic/Registry.cpp
@@ -185,6 +185,7 @@
   REGISTER_MATCHER(functionProtoType);
   REGISTER_MATCHER(functionTemplateDecl);
   REGISTER_MATCHER(functionType);
+  REGISTER_MATCHER(gnuNullExpr);
   REGISTER_MATCHER(gotoStmt);
   REGISTER_MATCHER(has);
   REGISTER_MATCHER(hasAncestor);