hidraw.c: fix permissions

Why the heck was this executable?
Revert "Makefile: make user append to CFLAGS instead of overwriting it"

This reverts commit 98f9432088604a9a9336d6b8458bd5e010832437. This was a
lazy trick from me to allow adding `-fsanitize=address` easier, but
apparantly not all users are so happy with it.

Conflicts:
	Makefile