different behaviour with different libs

[Mark Kent]

Hello,

What is the canonical way to compile programs that use posix threads
on freebsd 5.4+, with gcc?

I've seen comments that say that -pthread, used in 4.x, should go away
for 5.x.  But, for example, /usr/ports/security/openssl uses -pthread. 

So, use it?  Don't use it?  Should I care?

And what does it mean when a program works with one thread
library and not another?  I've got a case like this:

libpthread.so.1: chew up cpu, then SEGV
    libthr.so.1: chew up cpu, but works!
    libc_r.so.5: works great!

This is changed with libmap.conf.

Does this point to any particular shady coding practice?

Once I know that libc_r is my friend, does this suggest
a certain set of compile flags and/or link flags?

Thanks,
-mark