Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Use malloc() instead of alloca() to allocate a (potentially) large buffer
for storing the "diff -n" output. Some files (eg ports/INDEX,v) are too
big nowadays to fit on the stack.

Submitted by: Stephen Montgomery-Smith <stephen@math.missouri.edu>

The log file is more useful when line buffered.

Submitted by: Stephen Montgomery-Smith <stephen@math.missouri.edu>

No need to define externs for getopt interface.

Add `_PATH_DEVZERO'.
Use _PATH_* where where possible.

Use err(3). Use An/Aq for author name.

compare return value from getopt against -1 rather than EOF, per the final
posix standard on the topic.

Sweep through the tree fixing mmap() usage:

- Use MAP_FAILED instead of the constant -1 to indicate
failure (required by POSIX).
- Removed flag arguments of '0' (required by POSIX).
- Fixed code which expected an error return of 0.
- Fixed code which thought any address with the high bit set
was an error.
- Check for failure where no checks were present.

Discussed with: bde

Don't dump core on zero-size files.

Make the case where there is no changes look less fatal.

Check bogus and ignore against the relative name, not the absolute.

Improve mkctm.c so we can use it, and start using it.
This should help quite a bit on the load. Notice that
some minor changes in config files will be needed.
Contact me for details.

Commit the right version of mkCTM, <:-)

Noticed by: "Philippe Charnier" <charnier@lirmm.fr>

Update to current reality.
mkctm.c can replace the guts of mkCTM if anybody feels like it...