build: do not reply on header checking libinotify.h
but rather use the sys_bsd flag. The reason why relying on the header
existance is bad, is that bsd decided to install this header, with the
essential difference, that on bsd we require to link against libinotify,
which makes the compilation fail.
Reviewed-by: Mike Blumenkrantz <firstname.lastname@example.org>
Differential Revision: https://phab.enlightenment.org/D8093