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/
/** @page certificate-signals Certificate Signals
@signals
@signal certificate-stored
@signal certificate-deleted
@endsignals
@see certificate.h
<hr>
@signaldef certificate-stored
@signalproto
void (*certificate_stored)(PurpleCertificatePool *pool, const gchar *id, gpointer data);
@endsignalproto
@signaldesc
Emitted when a pool stores a certificate. Connect to the pool instance.
@param pool Pool the certificate has been stored into
@param id Key the certificate was stored under
@endsignaldef
@signaldef certificate-deleted
@signalproto
void (*certificate_deleted)(PurpleCertificatePool *pool, const gchar *id, gpointer data);
@endsignalproto
@signaldesc
Emitted when a pool deletes a certificate. Connect to the pool instance.
@param pool Pool the certificate was deleted from
@param id Key that was deleted
@endsignaldef
*/
// vim: syntax=c.doxygen tw=75 et