back-meta thread issues

[Aaron Richton <richton@nbcs.rutgers.edu>]

We are attempting to use back-meta to perform rewriting rules against
existing LDAP servers. We have settled on a configuration that appears to
work fine.

However, we have issues with copies of slapd compiled with thread support.
In this situation slapd becomes unreliable, often seg faulting or going
into a state where all queries are deferred. When attached to a debugger,
there seems to be no one particular function causing the segv. This occurs
under Solaris 9 4/03, both with the autodetected pthread implementation
and when I explicitly specify threads=lwp (which I'm sure takes effect as
libpthread.so.1 doesn't show up in an ldd of that binary.)

The same machine and configuration file, when running with a binary
compiled --without-threads, works perfectly. However, we would like to run
with threads enabled if at all possible. If anybody else has this working
and could provide some hints, or if we could get some pointers as to where
to start looking in the code, it would be much appreciated.

The working slapd was configured with:
./configure --enable-meta --enable-rewrite --with-cyrus-sasl=no
--enable-ldap --without-kerberos --without-threads --with-tls
--disable-bdb

and the non-working was identical save the "--without-threads".