boehm-gc: win32 getenv support, Tru64 cleanup

[Tom Tromey]

>>>>> "Hans" == Hans Boehm <Hans.Boehm@hp.com> writes:

Hans> In that case, I'd be inclined to check in the gc_priv.h part of the
Hans> workaround, just in case, but modify configure.in so the regular getenv
Hans> is used by default on all platforms, including win32, and the
Hans> workaround is off by default.  Does that sound right?

Sounds good to me.

Tom