sys/acl.h: move main typedefs to sys/_types.h

[brooks]

Summary

Make __ prefixed versions available without the pollution of sys/acl.h
(and by extension sys/param.h).

[kib]

Why not define __acl_type_t in sys/_types.h instead?

[brooks]

In D44382#1012183, @kib wrote:

Why not define __acl_type_t in sys/_types.h instead?

I could do that (presumably declaring all of them), but that doesn't solve the problem of needing to include sys/acl.h unless I s/acl_type_t/__acl_type_t/ in syscalls.master or do a bit of macro magic in _libsys.h. I was particularly trying to avoid pulling in sys/param.h since that significantly increases the polution in libc_private.h (for example it requires removing the MIN macro in qsort.c). I'm fine with other solutions, but this one was low impact.

I was briefly tempted to either use macros or just edit syscalls.master adding __ prefixes to make it work with sys/_types.h instead of sys/types.h, but that seemed a fair bit of churn and would also require expanding u_int and u_long. We could still go that way (or use macros to do it) if that makes sense.

[kib]

The intent was to use __acl_type_t in syscalls.master (and leaving it with sys/_types.h).

[brooks]

Declare __acl types in sys/_types.h