detect libxpm precense with autotools

[Pierre-Paul L. <pp...@nb...>]

Hi,

I need a macro for detecting libxpm precense on the system. Also a
way to turn XPM support on/off at ./configure time. I'm currently
using -DHAVE_XPM in scrapwm/src/Makefile.am which needs to be fixed.

Would you mind to write this nlevitt?