[m-dev.] Upgrading Boehm GC to version 7.6

[Julien Fischer]

Hi all,

I have been looking into the problems with the x86_64-*-cygwin port.
The major remaining issue is the linking issue in bug #398 -- this is a 
problem with the Boehm GC that has already been fixed upstream.  We can
backport that fix to our current version or upgrade our current version
of the collector to version 7.6.  Preferences?

Julien.