PATCH: Parse "class" as a tag

This patch is just the easy part of the class names patch, which
allows the parsing of "class" in addition to "struct" and "union" to
declare a record. So this patch allows:

  class C { };
  class C c1;

But it does not contain the lookup bits, so this won't work yet:

  C c2;

  - Doug

clang-class-key.patch (5.45 KB)

Applied, thanks Doug!