Attached patch removes special cases for the following unsupported targets as build and host environments:

- uwin*
- i370-*-opened* | i370-*-mvs*
- i[34567]86-*-sco3.2v5*
- i[34567]86-sequent-ptx4* | i[34567]86-sequent-sysv4*
- i[34567]86-*-sysv4*
- i[34567]86-*-udk*
- i[34567]86-*-uwin*
- i386-*-vsta
- powerpc-*-beos*

All were deleted as targets in 2008, except for i386-*-vsta which was removed in 2004.

OK to commit to trunk?

FX