[poppler] compile won't find fontconfig.h

[Jim Philips]

My compile of Poppler 9.4.2 fails every time because it can't find 
fontconfig.h. The file exists in /usr/X11R6/include/fontconfig/fontconfig.h 
and I've even tried adding the include path. But it fails every time anyway. 
The configure script doesn't seem to allow you to tell it where fontconfig is 
installed. So, is there anyway for me to build this?

I'm running Slackware 10.2