Problem when recompiling

Hi, i compiled php on a new server earlier today with the included mysql support. I later realised that i wanted to compile with a mysql-installation. So - i installed mysql and ran my install-script for php again: cd php-4.3.1 ./configure \ --with-mysql=/usr/local/mysql/current \ --with-apxs=/usr/local/www/bin/apxs \ --enable-trans-sid \ --enable-ftp \ --enable-track-vars \ --enable-inline-optimization make make install However...now it doesn't work. It runs on until: Configuring extensions checking for ZLIB support... no checking if the location of ZLIB install directory is defined... no configure: error: Cannot find libz Why did my compilation work so fine the first time - and not now when i am trying to recompile? - D