Fix typos in hint names.

MFC after:	1 week
Add an option for finding sparse files.

Reviewed by:	iedowse
MFC after:	3 weeks
Improves and enhances using the "installPackages=" variable.
Adds "pkgExt=" variable to set if pkgs are .tbz or .txz or other.
Auto-detects if packages are PKGNG or old PKG format.
Auto-bootstrap of PKGNG for the new installed environment.
Fixes issues with installing packages from local media, such as DVD/USB.

Switch to using a space-delimiter for installPackages, since a number
of packages use a "," in their version string.

Fix pc-sysinstall to ignore install scripts, and not hang on
user interaction prompts when installing pkgs.

Add pkg2ng command as apart of pkgng bootstrap process.

Obtained from:	PC-BSD
Use GNOP to force ZFS pools to 4k.

Obtained from:	PC-BSD
Plug memory leaks in file descriptors passing.
Use dedicated malloc type for filecaps-related data, so we can detect any
memory leaks easier.
Import libyaml 0.1.4 into vendor
For some reason when I started to pass filedescent structures instead of
pointers to the file structure receiving descriptors stopped to work when also
at least few kilobytes of data is being send. In the kernel the
soreceive_generic() function doesn't see control mbuf as the first mbuf and
unp_externalize() is never called, first 6(?) kilobytes of data is missing as
well on receiving end.

This breaks for example tmux.

I don't know yet why going from 8 bytes to sizeof(struct filedescent) per
descriptor (or even to 16 bytes per descriptor) breaks things, but to
work-around it for now use 8 bytes per file descriptor at the cost of memory
allocation.

Reported by:	flo, Diane Bruce, Jan Beich <jbeich@tormail.org>
Simple testcase provided by:	mjg
Constify where possible.

Approved by:	cperciva (mentor)
Due to calendar(1)'s abuse of the C preprocessor "unix" gets expanded to
"1".  'Fix' this.

PR:		bin/175790
Submitted by:	ak
Approved by:	cperciva (mentor)
Fix typo ('1' != 'l')

PR:		bin/175975
Submitted by:	William Ahern <william@25thandclement.com>
Approved by:	cperciva (mentor)
devd: Use volatile sig_atomic_t for the flag set by a signal handler.

Submitted by:	Christoph Mallon <christoph.mallon@gmx.de>
Approved by:	cperciva (mentor)
devd: Remove call to _exit() from signal handler, which also sets a stop flag.

Submitted by:	Christoph Mallon <christoph.mallon@gmx.de>
Approved by:	cperciva (mentor)
devd: Simplify while (1) { if (x) break; } to while (!x) {}.

Submitted by:	Christoph Mallon <christoph.mallon@gmx.de>
Approved by:	cperciva (mentor)
devd: Use the standard constructor of std::string instead of string("").

Submitted by:	Christoph Mallon <christoph.mallon@gmx.de>
Approved by:	cperciva (mentor)
devd: Avoid unnecessary temporary objects (and simplify the code) when handling std::string.

Submitted by:	Christoph Mallon <christoph.mallon@gmx.de>
Approved by:	cperciva (mentor)
devd: Remove empty virtual destructor from class, which has noch subclasses.

Submitted by:	Christoph Mallon <christoph.mallon@gmx.de>
Approved by:	cperciva (mentor)
devd: Remove unnecessary empty default constructors.

Submitted by:	Christoph Mallon <christoph.mallon@gmx.de>
Approved by:	cperciva (mentor)
devd: Use string::empty() instea of string::length() == 0.

Submitted by:	Christoph Mallon <christoph.mallon@gmx.de>
Approved by:	cperciva (mentor)
devd: Use simpler dst += *x instead of str.append(x, 1).

Submitted by:	Christoph Mallon <christoph.mallon@gmx.de>
Approved by:	cperciva (mentor)