Specifically, avoid building all plugins as non-static objects,
as well as some supplementary libraries. In fact, a large amount
of plugins was already gated to build as shared objects only with
WITHPIC=1, but this was not done consistently.
This gating has been moved to */p/Makefile.
Building these shared objects is a waste of time and breaks
the --without-pic build unless CFLAGS is forced in the make
invocation.