With the use of the full type for encoding type aliases, ptraliasenc's
simple check became invalid (it's purpose is to ensure the encoding
doesn't have "null" in it, not the exact encoding itself, but this is
good enough).
Attempting to add ev_ushort caused ptraliasenc to break, but that was
because it was already broken: I had implemented the scan of the xdef
table incorrectly, thus adding only 1 ev type resulted in the walked
pointer being out of phase with its data due to it first passing over
the type encodings (which is why adding long and ulong didn't cause any
obvious trouble).
