XmPrivate.h: Avoid whitespace problems (IMPROVED)

XmPrivate.h: Avoid whitespace problems (IMPROVED)

When applying a patch, "git am" strips
trailing whitespace, although they are
present in the git formatted-patch.

This way the committed file will be
slightly different than the file re-generated
by extractprototype.h

It shouldn't hurt, but next run of
extractprototype.h will add trailing spaces
again and the resulting diff on XmPrivate.h
will include more changes than actually
needed.

This may break some viscious circle after
applying the patch, so enabling regeneration
on LinuxArchitecture again.

This patch does not add XmeFlushIconFileCache()
needed by dtcreate.