Add an AST matcher for external formal linkage.

Patch by Visoiu Mistrih

llvm-svn: 278926
diff --git a/clang/lib/ASTMatchers/Dynamic/Registry.cpp b/clang/lib/ASTMatchers/Dynamic/Registry.cpp
index 192b4b6..6e594d7 100644
--- a/clang/lib/ASTMatchers/Dynamic/Registry.cpp
+++ b/clang/lib/ASTMatchers/Dynamic/Registry.cpp
@@ -226,6 +226,7 @@
   REGISTER_MATCHER(hasEitherOperand);
   REGISTER_MATCHER(hasElementType);
   REGISTER_MATCHER(hasElse);
+  REGISTER_MATCHER(hasExternalFormalLinkage);
   REGISTER_MATCHER(hasFalseExpression);
   REGISTER_MATCHER(hasGlobalStorage);
   REGISTER_MATCHER(hasImplicitDestinationType);