First attempt to fix a buildworld from -stable machine.  Explicitly include strtofflags.c from lib/libc/gen when building mtree until the current dependency mess with mtree is fixed.
First attempt to fix a buildworld from -stable machine.  Explicitly
include strtofflags.c from lib/libc/gen when building mtree until the
current dependency mess with mtree is fixed.

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