Remove source_rc_confs, inlined from defaults/rc.conf

Inlining source_rc_confs broke sysrc_test:A_flag

While here, switch to SPDX, bump version/copyrights, fixup comments.

Prevent common function

Remove source_rc_confs, inlined from defaults/rc.conf

Inlining source_rc_confs broke sysrc_test:A_flag

While here, switch to SPDX, bump version/copyrights, fixup comments.

Prevent common function override when bsdconfig includes new
sysrc.subr that contains inlined commons. Fix non-unique duplicate
header variable incorrectly shared between bsdconfig's sysrc.subr
include and new sysrc.subr include.

Harden RC_DEFAULTS parameter expansion from DoS-via-glob (SC2223).

Move pgm to the correct location to not override bsdconfig's pgm.

Drop _SYSRC_JAILED=1 that is no-longer needed. Drop i18n from
jail_depend now that messages are inlined to subr.

Reported by: siva
Fixes: eaeb5f29bc6f sysrc: make independant from bsdconfig(8)

show more ...

sysrc: make independant from bsdconfig(8)

MFC After: 1 week
Approved by: dteske
Reviewed by: dteske
Differential Revision: https://reviews.freebsd.org/D59658