Configuring PHP 4.0-RC1, or PHP 3.0.15, or PHP 3.0.15, the configure script fails to detect resource.h.  This may be --with and or --enable dependant, I am unsure, but I don't think it is, as resource.h is required for many core PHP functions/logic.  If it makes a difference, I configured like this :
./configure --with-apache=../apache_1.3.12 --with-mysql --with-mcrypt --with-ftp --with-gd --with-ttf --enable-track-vars --disable debug
            and
./configure --with-apxs=/usr/local/apache/bin/apxs --with-mysql --with-mcrypt --with-ftp --with-gd --with-ttf --enable-track-vars --disable debug

I even tried removing all but the mysql gd and ttf options, to no avail.  I have not delved into trying to patch the configure script, as I assume it is automagically generated from M4 macros or something similar.  The short term fix was to manually edit php_config.h, however this issue should be addressed.  I have seen other bugs in the database that may also relate to this issue.