Properly support png 1.5

Obtained from:	pkgsrc
- Readd empty directories to plist

Pointyhat to:	bapt
Mk/bsd.linux-apps.mk: bump sdl_image shlib.

- Use correct shlib version for sdl_image 1.2.12

PR:		196251
Differential Revision:	https://reviews.freebsd.org/D1366
Submitted by:	amdmi3
Approved by:	swills (mentor)
Approved by:	portmgr (swills)
Use a less kludgy way for handling libperl.so's versionning and linking.

Sponsored by:	Absolight
Explicitely disable gnutls as it fails to build if detected

Reported and tested by:	Scott Allendorf
Update security/gnupg*/pkg-message to reflect
reality.

Sponsored by:	The FreeBSD Foundation
Properly support png 1.5

Obtained from:	Gentoo
Remove some resurected ports
devel/linux-c6-libgfortran: add port

Necessary gfortran libs for Linux.

WWW: http://www.centos.org

Differential Revision:	https://reviews.freebsd.org/D1356
Requested by:	db
Approved by:	swills (mentor)
devel/linux-c6-devtools: add run dependency on linux-c6-libgfortran

- add RUN_DEPENDS for devel/linux-c6-libgfortran.

Differential Revision:	https://reviews.freebsd.org/D1357
Requested by:	db
Approved by:	swills (mentor)