[PATCH libXpm] Xpm.h public header file should be included unsing <X11/xpm.h>

[Mark Kettenis]

> From: Gaetan Nadon <memsize at videotron.ca>
> Date: Sat, 03 Dec 2011 22:03:48 -0500
> 
> The -I directive is adjusted accordingly.

Why?  To me, using "xpm.h" here makes more sense, since it indicates
that the xpm.h file that's present in the source tree is to be used
instead of the version that's already installed on the system.