UFS2: make di_extsize unsigned.

di_extsize is the EA size and as such it should be unsigned.
Adjust related types for consistency.

Reviewed by:	mckusick (previous version)
MFC after:	3 weeks
Add #ifdef wrapper around definitions so they aren't included multiple
times.
Break out the debug code into a new include file in preparation for
some more iwn work.
Return 0 if:

  1. "-u N" specified, no -f, and mdN found,
  2. no -u, "-f /pathname" specified, and mdN associated with /pathname found,
  3. "-u N" specified, "-f /pathname" specified, and both of them found,
  4. "-l" specified and no -f,
  5. "-l" specified, "-f /pathname" specified, and /pathname found.

otherwise return -1.

Spotted by:	Julian H. Stacey
Redefine the io provider using the SDT(9) macros instead of doing everything
manually. This change has no functional impact.

Discussed with:	gnn
Be more selective when filtering for lib*.so.N files.  These are deleted
at the end of the upgrade process, after warning users to upgrade any
3rd party software (e.g., from the ports tree) which might link to the
libraries being removed.

Prior to this commit, the line
  /usr/lib/libc.so|...|/lib/libc.so.7
matched the regex, which -- upgrading from 9.x to 10.x, where libc.so is
a regular file and thus was not part of a line which matched the regex --
resulted in freebsd-update thinking that /usr/lib/libc.so was a shared
library which was being removed as part of the upgrade.  This had some
unfortunate consequences.

This will be part of an upcoming Errata Notice.
Fix crossed fingers output. Only comment changed.
Add support for using "pkg+http://" for the PACKAGESITE.

pkg 1.2 is adding this support as well. This should help
lessen the confusion on why the default SRV PACKAGESITE
does not load in a browser.

Adapated from:	matthew's upstream pkg change
Approved by:	bapt
MFC after:	2 days
Install default FreeBSD pkg.conf
Wrap long lines
Simplify check for invalid pkg.conf
Move legacy pkg.conf reading into its own function
Parse repo-style /etc/pkg/FreeBSD.conf
Move fetching into fetch_to_fd()
Tell where PKG is coming from
Fetch pub and sig
Load fingerprints
Verify signature
Use simpler .sig bundle so only 1 fetch is needed
Tell which fingerprint a pkg is verified against