MFC: r257315, r260445, r264803

Update byacc to 20140422
MFC: r267131, r267132, r267133, r268493, r268671

Use NULL instead of 0 (Patch by Sascha Wildner <saw at online.de> for Dragonfly)
Remove unnecessary semicolons (Patch by Sascha Wildner <saw at online.de> for Dragonfly)
Add support for arbitrary http requests [1]
Support EAGAIN in fetch_writev

Submitted by:	Alex Hornung <alex at alexhornung.com> [1]
Reviewed by:	des
MFC: r267376

Add a zlib pkg-config file (more and more ports requires it)

Approved by:	delphij
MFC: r261032
Add quiet support for kldstat -n

PR:		bin/180014
Submitted by:	Olivier Cochard-Labbé <olivier at cochard.me>