I don't assume that make is bsdmake, only that it is something POSIX-compliant.
But you're right that I should use ${MAKE}, in case it isn't in the path. (I
don't know if anyone actually gets this right, but if make is not in the path
and is invoked via /path/to/make, then ${MAKE} should be "/path/to/make" and
not just "make".)
Can you try the attached patch?