ntdll: In find_file_in_dir(), don't test directory entries' short names if the target name isn't a short name.

hash_short_file_name() will always create a short name of at least 8 characters
with the 5th being a tilde (~).  If the target name isn't of that form, then it
can never match any short name constructed from the directory entries.

wined3d: Replace vendor specific callbacks with generic code that uses vendor specific renderer string tables.

ntdll: Fix the compilation by using the right mcontext_t field names for the signal context on FreeBSD.