Subject: ruby-1.9.2-p0 no more support for glibc-2.1.x - broken pthread

Up to ruby-1.9.1-p430 i could compile/link/production on old
glibc-2.1.x systems without problems (RedHat 6.2).

ruby-1.9.2-p0 still compiles/link and works but no more 100%
-> when i need threads i get:

  "ruby engine can initialize only in the main thread"

this is due changes in thread_pthread.c which has abandoned support
for systems without pthread_getattr_np setting STACKADDR_AVAILABLE
to 0 and raising the above message.

For me this is a severe regression - can this be fixed please?
I have some systems i cannot upgrade due to non-open source issues
and i need to have up-to-date ruby/rails on these.

Thanks for any help.

Regards
Axel