[MS] Accept __unaligned as a qualifier on member function pointers

We need to treat __unaligned like the other 'cvr' qualifiers when it
appears at the end of a function prototype. We weren't doing that in
some tentative parsing.

Fixes PR36638.

llvm-svn: 326962
diff --git a/clang/lib/Parse/ParseTentative.cpp b/clang/lib/Parse/ParseTentative.cpp
index 88c0e17..ebd6f0f 100644
--- a/clang/lib/Parse/ParseTentative.cpp
+++ b/clang/lib/Parse/ParseTentative.cpp
@@ -1894,7 +1894,8 @@
     return TPResult::Error;
 
   // cv-qualifier-seq
-  while (Tok.isOneOf(tok::kw_const, tok::kw_volatile, tok::kw_restrict))
+  while (Tok.isOneOf(tok::kw_const, tok::kw_volatile, tok::kw___unaligned,
+                     tok::kw_restrict))
     ConsumeToken();
 
   // ref-qualifier[opt]