funky library linking problems in Fedora Core 2 x86_64

[Nicholas Ritter]

While running Fedora Core 2 x86_64 on AMD Opterons I have noticed 
something odd about compiling programs which link to shared libraries. I 
have compiled a few apps (libgda, MySQL 3 and 4, PHP 4, to name a few) 
that I use configure to point to the dependent libraries (ie.: php's 
./configure --with-mysql=<dir>) and I notice that configure fails to see 
the library, even though the library is there. Even when I get the app 
to compile (so far in the case of libgda,) the app fails to work, and 
even acts as though it still failed to see and/or link to the library 
(ie.: libgda configure saw libmysqlclient, compiled without error, but 
errored out when used saying it could not find the libmysqlclient library.)

Double checking /etc/ld.so.conf and doing a ldconfig -p | grep <library 
name> finds the libraries, so they are there.

Anyone else seen this problem? Or is it something I am doing wrong. 
Fedore Core 2 for i386 didn't seem to do any of this.

Nicholas