Fix header output when -P is specified and (ncpus - 1) != maxid.

Reported by:	Hiroaki Shimizu
PR:		152738
Fix a bug which could break extended attributes in a dump output.
This occurred when a file was >892kB long and had a large data (>1kB)
in the extended attributes.

Reported by:	Masashi Toriumi
Reviewed by:	mckusick
Use the linker to perform relocations in the SUNW_dof section rather than
doing them in drti during startup. This fixes a number of problems with
using USDT probes in stripped executables and shared libraries, and with
USDT probes in static functions.

Reviewed by:	rpaulo
MFC after:	1 month
Sponsored by:	EMC / Isilon Storage Division
Phabric: 	D751
Update a stale comment.