lightly used. Find the proper .m file when we depend on *_if.[ch] in
the srcs line, with seat-belts for false positive matches. This uses
make's path mechanism. A further refinement would be to calculate this
once, and then pass the resulting _MPATH to modules submakes.
Differential Revision: https://reviews.freebsd.org/D2327
Tested on Qemu/KVM, VirtualBox, and BHyVe.
Currently built as modules-only on i386/amd64. Man pages not yet hooked
up, pending review.
Submitted by: Bryan Venteicher bryanv at daemoninthecloset dot org
Reviewed by: bz
MFC after: 4 weeks or so