PHP fails to 'make' with apache 2 for use as a '.so' lib.
The configure Script was:

./configure --with-mysql --enable-force-cgi-redirect --with-apxs2=/usr/local/apache2/bin/apxs

Configuring finished successfully, the make command stops with the following error message:

-------<snip>----------

Making all in apache2filter
make[2]: Entering directory `/tmp/php-4.0.6/sapi/apache2filter'
make[3]: Entering directory `/tmp/php-4.0.6/sapi/apache2filter'
/bin/sh /tmp/php-4.0.6/libtool --silent --mode=compile
gcc  -I. -I/tmp/php-4.0.6/sapi/apache2filter -I/tmp/php-4.0.6/main -I/tmp/ph
p-4.0.6 -I/usr/local/apache2/include -I/tmp/php-4.0.6/Zend -I/tmp/php-4.0.6/
ext/mysql/libmysql -I/tmp/php-4.0.6/ext/xml/expat/xmltok -I/tmp/php-4.0.6/ex
t/xml/expat/xmlparse -I/tmp/php-4.0.6/TSRM  -D_REENTRANT -DSUPPORT_UTF8 -DXM
L_BYTE_ORDER=12 -I../TSRM -DTHREAD=1 -g -O2 -pthread  -c sapi_apache2.c
sapi_apache2.c: In function `php_input_filter':
sapi_apache2.c:248: warning: passing arg 4 of `ap_get_brigade' from
incompatible pointer type
sapi_apache2.c: In function `php_output_filter':
sapi_apache2.c:337: too few arguments to function `ap_save_brigade'
sapi_apache2.c: In function `php_register_hook':
sapi_apache2.c:443: warning: passing arg 2 of `ap_register_input_filter'
from incompatible pointer type
make[3]: *** [sapi_apache2.lo] Error 1
make[3]: Leaving directory `/tmp/php-4.0.6/sapi/apache2filter'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/tmp/php-4.0.6/sapi/apache2filter'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/tmp/php-4.0.6/sapi'
make: *** [all-recursive] Error 1

-------<snip>----------