Make use of mk/ files from a fresh source tree, rather than the currently installed ones.  This makes it possible to use the script against Makefiles that uses bsd.own.mk on an old system.
Make use of mk/ files from a fresh source tree, rather than
the currently installed ones.  This makes it possible to use
the script against Makefiles that uses bsd.own.mk on an old
system.

Submitted by:	bushman

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase