Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFH (r251810): fix installation from read-only .OBJDIR
MFH (r255384): add PRIVATELIB for internal-use shred libraries
MFH (r255385, r255413): add a stock libmap32.conf
MFH (r255765): always support directory mapping; rewrite libmap man page

MFC: 234851, 235059

Add two special directives to libmap.conf:
include <file>:
Parse the contents of file before continuing with the current file.
includedir <dir>:
Parse the contents of every file in dir that ends in .conf before continuing
with the current file.
Any file or directory encountered while processing include or includedir
directives will be parsed exactly once, even if it is encountered multiple
times.

Approved by: des (mentor)

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

- Be explicit about libmap32.conf only working on amd64

Requested by: ru

- Document libmap32.conf

MFC after: 1 week

Update example libmap.conf file:
- Remove pointless examples that map libpthread to itself.
- Update shared libraries for 6.0 bumps.

Reported by: rwatson
MFC after: 1 day

Correct some grammar.

Document methods people use to load linux shared libraries in FreeBSD
binaries. A very neat trick.

Sort sections.

Assorted markup, spelling, and grammar fixes.

Correct a spelling error.

Support basename and path based constrained matches.

eg:
[foo]
...

matches any executable 'foo'

[/usr/bin/foo/]
...

matches any executable under the directory /usr/bin/foo/

Exact matches continue to function as before.

PR: bin/66769
Submitted-by: Dan Nelson

deischen had a good idea on how to make my previous commit a little better,
update accordingly.

Suggested by: deischen

Update this manual page for the libkse -> libpthread changes.

Discussed with: deischen

Retire the WITH_LIBMAP compile knob; libmap is now a standard feature.

Assorted mdoc(7) fixes.

Dynamic object dependency mapping: libmap.

This is an optional feature, disabled by default.

This will be useful to people testing the various POSIX threading
libraries under -CURRENT but can easily serve other needs.