Path discovery and simplification of libffi-unix.lisp

[Liam Healy]

I'm trying to catch up on recent changes made to CFFI with regard to
path discovery with the idea of simplifying code, both in CFFI itself,
and in GSLL (which uses CFFI). The grovel option pkg-config-cflags
seems to permit the elimination of some other code in e.g.
libffi-unix.lisp. With the presence of (pkg-config-cflags "libffi"
:optional t), it seems like these could be eliminated:

#+darwin
(cc-flags "-I/opt/local/include/")

#+openbsd
(cc-flags "-I/usr/local/include")

and these

#+darwin
(include "ffi/ffi.h")
#-darwin
(include "ffi.h")

could be replaced with
(include "ffi.h")

Is that correct? Not a darwin or openbsd user so can't test myself.

Thanks,
Liam