Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

More -Wmissing-variable-declarations fixes.

In addition to adding `static' where possible:

- bin/date: Move `retval' into extern.h to make it visible to date.c.
- bin/ed: Move globally used variables into ed.h.
- sbin/camcontrol: Move `verbose' into camcontrol.h and fix shadow warnings.
- usr.bin/calendar: Remove unneeded variables.
- usr.bin/chat: Make `line' local instead of global.
- usr.bin/elfdump: Comment out unneeded function.
- usr.bin/rlogin: Use _Noreturn instead of __dead2.
- usr.bin/tset: Pull `Ospeed' into extern.h.
- usr.sbin/mfiutil: Put global variables in mfiutil.h.
- usr.sbin/pkg: Remove unused `os_corres'.
- usr.sbin/quotaon, usr.sbin/repquota: Remove unused `qfname'.

Spelling fixes for libexec/

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.