Rename pkgs to more generic targets (that's what they are)

Reviewed by:	marcel
Put lib/csu/amd64/Makefile back the way it is in head
and handle staging via ../Makefile.inc
Renamed pkgs/ targets/
all is MAIN target
Need headers staged by libpam
update dependencies
If we are doing META_MODE use targets/Makefile as top-level
since this one isn't suitable.
Add STALE_STAGED as default no