pidgin/pidgin

Fix an issue where color_is_visible was incorrectly comparing unsigned values that were potentially wrapping.

Testing Done:
Compile only.

Reviewed at https://reviews.imfreedom.org/r/493/
prefix=@prefix@
exec_prefix=@exec_prefix@
libdir=@libdir@
includedir=@includedir@
datarootdir=@datarootdir@
datadir=@datadir@
sysconfdir=@sysconfdir@
abs_srcdir=@abs_srcdir@
abs_builddir=@abs_builddir@
plugindir=${libdir}/pidgin
Name: Pidgin
Description: Pidgin is a GTK2-based instant messenger application.
Version: @VERSION@
Requires: gtk+-2.0 purple
Cflags: -I${abs_srcdir}