Implemented more or less as described in the pcrejit(3) manpage, and
adds some compatibility defines for use with older pre-8.20 libraries
that do not have this functionality.

Fixes: #1080

Fixes #1122

Fixes #1069

argument to a printflike function.

Needed to test #1123

Varnishtest doesn't see the difference between a VCC core dump and
a VCC error, so a test-case is non-trivial.

Fixes	#1126

Fixes #1125

The following patch allows the autoconf script to detect the presence of
libedit when there isn't a pkg-config file present and thus allowing
Varnish to detect libedit on OpenBSD/FreeBSD/NetBSD/DragonFly.

Fixes: #1003

I've opted for a less intrusive fix that Martin proposed, but my fix
is largely a rework of his suggested patch.

Testcase by:	Martin

Submitted by:	scoof
Fixes		#1104

pointer, in order to not have dependency between trouble entry and
objhead lifetime.

Fixes	#1091

Submitted by:	DocWilco

the original requester.

Submitted by:	DocWilco