Go in gcc 4.7

[Ian Lance Taylor]

Andreas Schwab <schwab@linux-m68k.org> writes:

> Ian Lance Taylor <iant@google.com> writes:
>
>> The functions required are makecontext, getcontext, and setcontext.
>
> Note that these functions are obsolescent in POSIX.1-2004 and removed
> from POSIX.1-2008.

I know, but they were removed with no adequate replacement.  POSIX
suggests that you can simply use pthreads, but that does not suffice for
Go's needs.

Ian