Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

ANSIfy ldconfig and the aout bits it still uses from rtld-aout.

(Why is aout support still there?)

64-bit clean + WARNS=6:
- Convert the (char *) cast+cast backs magic to
memcpy(3). Without this, the resulting code
is potentially risky with higher optimization
levels.
- Avoid same name when calling local variables,
as well as global symbols. This reduces
confusion for both human and compiler.
- Add necessary casts, consts
- Use new style function defination.
- Minor style.Makefile(5) tweak
- Bump WARNS?= from 0 to 6

** for the aout code: changes are intentionally limited
to ease maintaince.

Restore these files to make ldconfig(8) happy.