Recursive make should be invoked as $(MAKE) and not "make" for reasons
documented at
https://www.gnu.org/software/make/manual/html_node/MAKE-Variable.html
$(MAKE) is what CMake puts in all the CMakeFiles/Makefile2 it generates,
it doesn't use "make" either.
Issue found thanks to the following warning:
build.log:make[4]: warning: jobserver unavailable: using -j1.
Add '+' to parent make rule.
If CMake is invoked with -GNinja or other then fall back on "make" as
before and pray that it's available.
Fast reproduction with:
make -j2 -C build clean mylib_project VERBOSE=1
Build directories have been compared before/after this change and
there's zero difference except the generated
mylib_project.dir/build.make file (and the warning above) when using
make.
Signed-off-by: Marc Herbert <marc.herbert@intel.com>
d8c5c9dcf1