I wanted to get the GIF support present in GD 2.0.28. However under RedHat Linux 6.2, compiling PHP 4.3.8 will fail with a undefined reference to `gdFreeFontCache' error when using GD-2.0.28.
Use PHP 4.3.9RC2 or later. It has GD 2.0.28 bundled with it and compiles like a champ.
This little problem represented an hour of my life.