This patch strips out all of the references to ganglocal memory in gcc.
Unfortunately, the runtime api still takes a shared memory parameter, so
I haven't made any changes there yet. Perhaps we could still keep the
shared memory argument to GOACC_parallel, but remove all of the support
for ganglocal mappings. Then again, maybe we still need support
ganglocal mappings for legacy purposes.

With the ganglocal mapping aside, I'm in favor of leaving the shared
memory argument to GOACC_parallel, just in case we find another use for
shared memory in the future.

Nathan, what do you want to do here?

Cesar