When compiling PHP with FreeType 2 support, you'll probably have some problems if - for example - you use debian and didn't compile freetype2 yourself...
If configure fails after saying "If configure fails, try --with-xpm-dir..." you most likely have FreeType1 installed, but not freetype2 ...
Do this as root :
apt-get install libfreetype6-dev
It took me some time to find out that apt-get install freetype2 is actually installing freetype1 ...