Log Message:
Update patch-ad so instead of getting rid of -ldl (which is needed
by Linux) in tests, use value of BUILDLINK_LDADD.dl.
Also use PTHREAD_LIBS instead of hard-coded -lpthread.

Include dlopen.buildlink3.mk and include pthread.buildlink3.mk.

This fixes problem on Linux and DragonFly where it was not
built with silc support.

Okayed by maintainer.

I tested this on Linux, DragonFly and NetBSD 2.0.2.

I also filed a bug report with gaim last week so they can fix the
configure.ac correctly.