Configured PHP 4.0.4 on AIX 4.3.3 using IBM C for AIX v.5 
Apache 1.3.9 in /usr/local/etc/apache

Installed via the following:
export CC='cc -Dinline= -ma'
./configure --with-apxs=/usr/local/etc/apache/bin/apxs --with-mysql=/usr/local --with-gd=/usr/local --with-ttf \ --with-informix
make; make install

everything appears to run fine (with the exception of some small errors about unrecognized suffixes), but when I start apache, I get:

[root@p140 php-4.0.4]# /usr/local/etc/apache/bin/apachectl start
Syntax error on line 208 of /usr/local/etc/apache/conf/httpd.conf:
Cannot load /usr/local/etc/apache/libexec/libphp4.so into server: dlopen: /usr/local/etc/apache/libexec/libphp4.so: No such file or directory /usr/local/etc/apache/bin/apachectl start: httpd could not be started

If I run configure with ONLY the --with-apxs and --with-mysql options, it compiles and installs, and apache runs fine.  If I remove --with-informix, same thing.  If I remove the --with-gd and related, same thing.

I've set INFORMIXDIR appropriately, and have the informix SDK installed (I've built this module successfully in Linux).

I've installed the gd,zlib,libjpeg,and freetype from bull.de, and manually built them as well.  No difference.

Apache modules installed:

[root@p140 local]# /usr/local/etc/apache/bin/httpd -l
Compiled-in modules:
  http_core.c
  mod_env.c
  mod_log_config.c
  mod_mime.c
  mod_negotiation.c
  mod_status.c
  mod_include.c
  mod_autoindex.c
  mod_dir.c
  mod_cgi.c
  mod_asis.c
  mod_imap.c
  mod_actions.c
  mod_userdir.c
  mod_alias.c
  mod_access.c
  mod_auth.c
  mod_so.c
  mod_setenvif.c