Move Objective-C ports to the v2 GNUstep ABI.
* GNUstep-back does not work with lld, so mark it to use Gold (BFD LD doesn't seem able to link Objective-C things). * Turn off some annoying debug logs in GNUstep back, which generate several messages per second when you move the mouse. These should never have been enabled in a release build anyway. * Downgrade Cenon to 4.0.2. This was the last version to actually work with GNUstep (the later ones use XCode >= 5 .xib files, which GNUstep can't parse). * Update gorm to git head. The current release doesn't work with the new Objective-C ABI, but -head has the patches to fix it. * Update PikoPixel and add it to the gnustep-app meta-package. * Update GNUstep -gui to the latest release. * Update gnumail and pantomime to the latest release and fix a linking error with the new ABI. * Update GNUstep FTP to the latest version.
It's been a while since I made any ports commits, so review would be appreciated.
This depends on https://reviews.freebsd.org/D18672 being committed.