Removing PORTNAME from libpq/Makefile

In order to have a shared libpq made automatically for AIX ports, it's
necessary to rework the shared lib rules in interfaces/libpq/Makefile.

It seems to me that the PORTNAME dependent rules should be in the
respective makefiles/Makefile.$(PORTNAME), no?

The libpq$(DLSUFFIX) make should be handled by %$(DLSUFFIX) rules for
that port.  If it needs extra handling, then there should be special
rules for libpq$(DLSUFFIX).

The various LDFLAGS_SL would be appended to the SHARED_LIB line in
the template and $(CFLAGS_SL) would then be used in the make rule for
the shared lib.

The most basic thing to do for this is to move the $(shlib) rule to
each Makefile.$(PORTNAME) and replace it in the libpq Makefile with a
simple rule to make libpq.o and then let each port make the shlib in
its own way.

It's not as complicated or as messy as it reads.  I need someone for
the linux, bsd, i386-solaris, univel and hpux ports to work with on
moving the shlib rule.  Better than just moving it over myself and
breaking it in the process. :)

So to summarize a little, in libpq/Makefile, make a libpq.o and then
in Makefile.$(PORTNAME), make the shared libpq.  Seem reasonable?

Thanks,
darrenk