Drop VMS?

[Zack Weinberg]

I propose we drop support for vax-dec-vms and alpha-dec-vms in the
mainline.

- I estimate >99% chance they do not compile at this time.

- There have been no changes made to VMS support code other than by
  global search and replace (i.e. not specific to VMS) since 1998.

- VMS support code is are responsible for >75% of the disgusting hacks
  in the config directory.

- Should there be renewed interest in GCC on VMS in the future, it
  will be easier for porters to start from scratch.  That is how
  grotty and out-of-date the existing code is.

- Previous inquiries about the existence of a GCC user community on
  VMS have turned up completely blank.

zw