mod_php4 core dumps with some extensions

I am not sure that is right list to ask... but I have some mysterious problems with mod_php. In short, apache core dumps at startup. gdb /usr/sbin/httpd core points to nonexistent address :( mod_php4 was build with apxs as so and several extensions (gd, zlib, dba, mysql, oci8) were also built as so (=shared). If I disable all extensions everything works fine. If I enable any module except mysql and oci8 everything works fine too. mysql.so also works if it was complied with --with-mysql=shared. But if I use --with-mysql=shared,/usr apache coredumps again... The only difference I see between mysql.so compiled with /usr and without it is that /usr/lib/libmysqlclient.so is linked to libpthread while the library that comes with php4 is not. Oracle client libraries were also linked with pthread... Then I have tried to start apache with LD_PRELOAD=libpthread.so and it worked! The other way to make apache work is to swap lines AddModule mod_ssl.c and AddModule mod_php4.c... so without mod_ssl or with mod_ssl loaded after mod_php4 everything works again. Then I have tried to link libphp.so with libpthread and that also solves all problems... Why? That is very strange... Why I don't see core dumps with LD_PRELOAD? Why don't I see core dumps if I place mod_ssl.c AFTER mod_php4? How is it all related to libpthread?? It seems like if libpthread is somehow loaded before mod_ssl that solves the problem... I have tried mod_ssl list without any luck :( I am not sure that is a php problem as core dumps go away if I disable mod_ssl. But they also go away with php3... I don't understand why all this workarounds work... That makes me suspect that something is completely wrong with my php... To 100% reproduce the problem you need a mod_ssl and php both built as so and mysql built with-mysql=shared,/usr (as an official mysql client library is built with tread-safe option)... Can anybody shade some light on my problem? Are there any know issues with mod_php4 and libpthreaded extensions and mod_ssl? Oleg