Configure problems on dual MySQL machine

I'm hoping to gradually transition my FreeBSD 4.7 web server from MySQL 
3.23 and PHP 4.3 to MySQL 4.1.7 and PHP 5.0.2.  I've successfully 
installed MySQL 4.1.7 into a separate directory and given it a distinct 
port and Unix socket, and it seems to be running happily alongside its 
older counterpart.

The problem arises when I attempt to configure PHP 5.0.2 from source. 
I'm trying to specify the version of MySQL to use by specifying to 
configure:

./configure --with-mysql=/usr/local/mysql4 
--with-mysqli=/usr/local/mysql4/bin/mysql_config

But configure errors out with:

checking for mysql_set_server_option in -lmysqlclient... no
configure: error: wrong mysql library version or lib not found. Check 
config.log for more information.

Looking at config.log reveals that configure is attempting to link to 
MySQL using a command like:

gcc -o conftest -g -O2 -R/usr/local/lib/ -L/usr/local/lib 
-R/usr/local/mysql4/lib/mysql -L/usr/local/mysql4/lib/mysql ...

I believe the problem is that configure is searching /usr/local/lib 
before it searches /usr/local/mysql4/lib/mysql, and so it is linking 
with the older MySQL 3.23 libraries.  It seems to prepend /usr/local/lib 
to the library search path between the check for mysql_close and the 
check for mysql_set_server_option.  I'm not sure why.

Does someone know of a way to convince configure to keep 
/usr/local/mysql4/lib/mysql before /usr/local/lib in the search path, so 
  it will find the right libraries?


Thanks,

--Stuart A. Malone
   Llamagraphics, Inc.