Unable to compile PHP 5.2.4 with mysql extension on Hp-UX 11.11

I've been unable to compile PHP 5.2.4 on HP-UX 11.11 with the mysql
extension against a 64bit mysql installation.

configure:59871: gcc -o conftest -I/usr/local/include -g -O2 -
D_XOPEN_SOURCE_EXTENDED -L/usr/local/mysql/lib -L/usr/local/mysql/lib -
liconv -L/usr/local/lib -L/usr/local/lib/gcc/hppa2.0w-hp-
hpux11.11/4.2.1 -L/usr/local/lib/gcc/hppa2.0w-hp-hpux11.11/4.2.1 -L/
usr/local/lib -L/usr/local/lib -L/usr -L/usr conftest.c -lmysqlclient
-lz -liconv -lz -lm -lnsl -lgcc -lxml2 -lz -liconv -lm -lxml2 -lz -
liconv -lm 1>&5
/usr/ccs/bin/ld: /usr/local/mysql/lib/libmysqlclient.a: Not a valid
library (invalid magic number). Possibly a 64-bit PA archive library
(Mismatched ABI).

Versions
#/usr/local/mysql/bin/mysql --version
/usr/local/mysql/bin/mysql Ver 14.12 Distrib 5.0.37, for hp-hpux11.11
(hppa2.0w) using readline 5.0
#gcc -v
Using built-in specs.
Target: hppa2.0w-hp-hpux11.11
Configured with: ../gcc/configure
Thread model: posix
gcc version 4.2.1
#