MFC r284406:

Use cpp -I$includedir

MFC r284289,r288267:

r284289:
Misc fixes from projects/bmake
r288267:
Remove redundant .NOPATH.

Bulk sync of pf changes from head, in attempt to fixup broken build I
made in r263029.

Merge r257186,257215,257349,259736,261797.

These changesets split pfvar.h into several smaller headers and make
userland utilities to include only some of them.

Bulk sync of pf changes from head, in attempt to fixup broken build I
made in r263029.

Merge r257186,257215,257349,259736,261797.

These changesets split pfvar.h into several smaller headers and make
userland utilities to include only some of them.