Also remove the horrible violation of the architectural rules by adding an include path into net in sched/group/Make.defs. Folks, if you are going to participate in this project, you MUST respect the odule architecture and never, never, never do these things.
commit d07afc934e, "fcntl: add O_CLOEXEC/FD_CLOEXEC support" introduce a compilation error .. a bad file inclusion. That commit added an unnecessary inclusion of "socket/socket.h" which is NOT available in the sched sub-directory. It is only available under the net/ sub-directory.
There is no include path for such and inclusion and there must NEVER be such a include path. Module design forbids including header files between diffent "silos" in the design. Nothing under net/ can ever be available to logic under sched/.