Thread+GC issues on ARM

[Neil Jerram]

Hi there!

Just in case anyone else is looking at this too, I just wanted to
announce that I'm investigating why the Debian Guile 2.0.3 fails to pass
'make check' on ARM, as can be seen here:
https://buildd.debian.org/status/package.php?p=guile-2.0.  Now that
there's a Debian package for Guile 2.0 - thanks Rob! - I couldn't resist
trying to build it on my GTA04.

It all looks quite tractable - just complex interactions between when
Guile's thread finalizer (on_thread_exit) runs, libgc's own
finalizer/cleanup, and the fact that Guile's finalizer re-registers with
the GC.

Also I think I might be able to throw light on the longstanding
threads.test hang
(http://www.mail-archive.com/address@hidden/msg06007.html).  When I
hit that in GDB, there were only 3 threads known to GDB, but libgc's
thread count was 4, and that will obviously cause libgc to hang.

So, more soon, I hope.

        Neil