Compiling a SOAP extension for PHP5 in MaxOSX Leopard

Hi.

I thought I'd try to compile a SOAP extension for the stock PHP 
installation in MacOSX Leopard.

I snagged the php-5.2.5 sources from php.net, and used the compile 
arguments found with the "php -i" command.  I only added "--with 
soap=shared --enable-shared" and removed everything mysql-related, like 
this:

../configure '--prefix=/usr' '--mandir=/usr/share/man' 
'--infodir=/usr/share/info' '--disable-dependency-tracking' 
'--with-apxs2=/usr/sbin/apxs' '--with-ldap=/usr' '--with-kerberos=/usr' 
'--enable-cli' '--with-zlib-dir=/usr' '--enable-trans-sid' '--with-xml' 
'--enable-exif' '--enable-ftp' '--enable-mbstring' '--enable-mbregex' 
'--enable-dbx' '--enable-sockets' '--with-iodbc=/usr' '--with-curl=/usr' 
'--with-config-file-path=/etc' '--sysconfdir=/private/etc' 
'--with-openssl' '--with-xmlrpc' '--with-xsl=/usr' '--with-pear' 
--enable-soap=shared --enable-shared

"make" runs and builds just fine after this.

Then I:
- copy php_src/modules/soap.so to 
/usr/lib/php/extensions/no-debug-non-zts-20060613/
- set extension_dir="/usr/lib/php/extensions/no-debug-non-zts-20060613/" 
and add extension=soap.so in /private/etc/php.ini

If I run "php -i" now, I get

dyld: NSLinkModule() error
dyld: Symbol not found: _OnUpdateLong
Referenced from:
   /usr/lib/php/extensions/no-debug-non-zts-20060613/soap.so
   Expected in: flat namespace
Trace/BPT trap

I found an OnUpdateLong function in php_src/ext/zlib/zlib.c, but I don't 
know if that's relevant.

What am I doing wrong?

(Yes, I know that there are several third-party stand alone php 
intallations for MacOSX (MacPorts, Fink, Entropy...), but I'd really 
like to just make the stock PHP work.  It's only a matter of one extra 
module, which shouldn't be a problem.  Right?)

Best regards,
Henrik