pidgin/pidgin

Use LT_LIB_M to determine if we need to link to the math library and link Pidgin to the X11 libraries
release-2.x.y
2021-04-11, Gary Kramlich
132d17234930
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 cmd-signals Command Signals
@signals
@signal cmd-added
@signal cmd-removed
@endsignals
@see cmds.h
@signaldef cmd-added
@signalproto
void (*cmd_added)(const char *command, PurpleCmdPriority priority,
PurpleCmdFlag flag);
@endsignalproto
@signaldesc
Emitted when a new command is added.
@param command The new command.
@param priority The priority of the new command.
@param flag The command flags.
@endsignaldef
@signaldef cmd-removed
@signalproto
void (*cmd_removed)(const char *command);
@endsignalproto
@signaldesc
Emitted when a command is removed.
@param command The removed command.
@endsignaldef
*/