Patch to allow Ada to work with tree-ssa

[Richard Kenner]

    I certainly would support removing all variable sized types from GNU C.
    There are too many language corner cases that have *never* worked, and
    this feature is not useful enough to justify working them all out.

On the other hand, there's *very little* code in the C front end to
support this (and most of what little there is will soon be moved from
c-gimplify.c to gimplify.c), so I see little cost in retaining it.

Why remove something that's mostly worked for over a decade and
people may well be using?