Parallel make fixes

Parallel make fixes

Fixes several problems with parallel makes in the current source:
- Add '+' prefix to many top-level Makefile commands. This informs make that
the following command should be treated as a sub-make and propagates the -jN
flag.
- Add a few missing dependencies
- Tweak some Makefiles that work with generated header files to prevent cases
where we attempt to use the file while it's being generated
- For the Linux kernel build, eliminate duplicated effort between COMPDIRS
and INSTDIRS, which also prevents conflict between the two in a
parallel situation.

FIXES 125031

Reviewed-on: http://gerrit.openafs.org/3
Verified-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>