The main objective here is to make it easy to identify what needs to change
in order to use a different sysent generator than the current Lua-based one,
which may be used to MFC some of the changes that have happened so we can
avoid parallel accidents in stable branches, for instance.
As a secondary objective, it's now feasible to override the generator on a
per-Makefile basis if needed, so that one could refactor their Makefile to
use this while pinning generation to the legacy makesyscalls.sh. I don't
anticipate any consistent need for such a thing, but it's low-effort to
achieve.
r355473 vastly improved the readability and cleanliness of these Makefiles.
Every single one of them follows the same pattern and duplicates the exact
same logic.
Now that we have GENERATED/SRCS, split SRCS up into the two parameters we'll
use for ${MAKESYSCALLS} rather than assuming a specific ordering of SRCS and
include a common sysent.mk to handle the rest. This makes it less tedious to
make sweeping changes.
Some default values are provided for GENERATED/SYSENT_*; almost all of these
just use a 'syscalls.master' and 'syscalls.conf' in cwd, and they all use
effectively the same filenames with an arbitrary prefix. Most ABIs will be
able to get away with just setting GENERATED_PREFIX and including
^/sys/conf/sysent.mk, while others only need light additions. kern/Makefile
is the notable exception, as it doesn't take a SYSENT_CONF and the generated
files are spread out between ^/sys/kern and ^/sys/sys, but it otherwise fits
the pattern enough to use the common version.
Reviewed by: brooks, imp
Nice!: emaste
Differential Revision: https://reviews.freebsd.org/D23197
