MFC r227838, r227873, r228025, r228049, r228289, r228447, r230753:

MFC r227838, r227873, r228025, r228049, r228289, r228447, r230753:

r227838, r227873:

Add new options, -e and -x, to display process environment variables
and ELF auxiliary vectors.

r228025, r228049:

Make proctstat -x output more readable.

This also fixes the issue, spotted by mdf, with values that were
printed as decimal and had hex prefixes.

Discussed with:	kib, rwatson

r228289:

Don't output a warning if kern.proc.auxv sysctl has returned EPERM.
After r228288 this is rather a normal situation.

r228447:

Make 64-bit procstat output ELF auxiliary vectors for 32-bit processes.

Reviewed by:	kib

r230753:

Always return 0 if the sysctl failed.

This fixes the bug: when procstat -xa was run and the sysctl for a
process returned ESRCH or EPERM, for this process procstat output the
result collected for the previous successful process.

git-svn-id: svn://svn.freebsd.org/base/stable/9@230917 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f