"make" vs "$(MAKE)" in tools/testing/selftests/Makefile

Hello,

Is there a reason why kselftest Makefile uses plain "make" instead of "$(MAKE)"?

Because of this, "make kselftest TARGETS=bpf -j12" ends up building all bpf tests sequentially, since the top make's jobserver is not shared with its children. Replacing "make" with "$(MAKE)" helps, but since other Makefiles use "$(MAKE)", it looks as if this has been done intentionally.

Best regards, Ilya