[PATCH] Fix PR c/6660

[Jim Wilson]

I searched the msdn site a bit and found this:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclang/html/_clang_structure_declarations.asp
The last paragraph talks about anonymous structures.  This isn't really enough
detail here for a language extension, but I see no intent here to allow
use of anonymous typedefed types inside a structure.

For extra points, I looked up the Plan9 reference.
http://plan9.bell-labs.com/sys/doc/comp.html
This is about 2/3 of the way down, in a section called "extensions".
There is a little more detail here, but still not as much as I'd like to see.
This one explicitly allows anonymous typedefs within a structure.  It also
goes a little farther and allows one to use the super-struct in contexts
where the base-struct is required, kind of like C++ (though I probably have
the terminology wrong).

Jim