Fix crash on missing namespace name in namespace alias definition -- PR14085.

Patch from Brian Brooks <brooks.brian@gmail.com>!



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@166893 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index 492250d..4cb14e2 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -88,6 +88,12 @@
   }
 
   if (Tok.is(tok::equal)) {
+    if (Ident == 0) {
+      Diag(Tok, diag::err_expected_ident);
+      // Skip to end of the definition and eat the ';'.
+      SkipUntil(tok::semi);
+      return 0;
+    }
     if (!attrs.empty())
       Diag(attrTok, diag::err_unexpected_namespace_attributes_alias);
     if (InlineLoc.isValid())