pidgin/pidgin

Use LT_LIB_M to determine if we need to link to the math library and link Pidgin to the X11 libraries

Gentoo ran into an issue with the gold linker without -lm. The original patch
and work came from Justin Lechner. https://bugs.gentoo.org/386079

Gentoo also ran into an issue with X11_LIBS not being added to pidgin. This
should already be implicit everywhere except for homebrew which patches X11
out of their build. Original patch/work came from and. https://bugs.gentoo.org/500762

Testing Done:
Installed and ran locally.

Reviewed at https://reviews.imfreedom.org/r/608/
/* This file is part of the Project Athena Zephyr Notification System.
* It contains source for the ZClosePort function.
*
* Created by: Robert French
*
* Copyright (c) 1987 by the Massachusetts Institute of Technology.
* For copying and distribution information, see the file
* "mit-copyright.h".
*/
#include "internal.h"
Code_t ZClosePort()
{
if (__Zephyr_fd >= 0 && __Zephyr_open)
(void) close(__Zephyr_fd);
__Zephyr_fd = -1;
__Zephyr_open = 0;
return (ZERR_NONE);
}