+ Builds and installs. Works so with IRC.

- does not install pidgin.1 in doc/Makefile. Why? finch does it.
- options.mk: is this sufficient?
- gstreamer should be a suggested option
- pidgin/Makefile.am, pidgin/Makefile.in should be patched to use an
  already installed libpurple ("pkg-config --libs purple",
  "pkg-config --cflags purple") to avoid the hack of linking libpurple.la
  from the .buildlink directory.