Implemented native DPMI code execution for x86-64.
Only tested with a simple Openwatcom "wcc hello.c" but
that works. It needed a few workarounds involving %ss
and in particular a nasty hack for %fs (used for TLS).


git-svn-id: https://dosemu.svn.sourceforge.net/svnroot/dosemu/trunk@1614 7758b857-130e-0410-ab9c-d8735a528d18