I haven't been able to run any Gecko-based browser (mozilla [|-stable], 
galeon, phoenix all tried) since the pthread changes on Alpha.  The process 
doesn't core.  This is what I get in gdb on mozilla-bin and phoenix:

nbsd_thread_create_inferior: td_open: process callback error

I've deleted all packages down to and including glib (and pkg_delete -r 
pth), removed ~/.mozilla, and rebuilt many times...  The last time it ran 
without error was with a 1.6J userland and 1.6L kernel.  Gecko browsers 
have failed with the above thread error on 1.6J with 1.6M kernel, and now 
1.6N userland + kernel.

Apologies for the x-post, this one's in a gray area.
Dave