ports-mgmt/pkg-devel: update to 2.0 beta1

Changes:

• the pkg target ABI is now dynamically detected, pkg can be used to cross install packages among OS.
• macho ABI handling completly rewritten
• ALTABI is not used anywhere anymore, we are now only working with ABI
• Lots of cleanups thanks for compiler sanitizers
• shlibs handling is now portable (and do not depend on elfhints anymore)
• deprecate ALLOW_BASE_SHLIBS, now pkg scans for /lib and /usr/lib (respecting rootdir) to find the list of shlibs provided by base. This scan is skipped when using pkgbase.
• new SHLIB_REQUIRE_IGNORE_GLOB and SHLIB_REQUIRE_IGNORE_REGEX to filter out some librariries to be added to shlibs_required list
• speed up pkg repo by using buffered stdio
• pkg now tracks shlibs with tagging: libfoo.so.1.0.0 - native (no change to status quo) libfoo.so.1.0.0:32 - compat 32 libfoo.so.1.0.0:Linux - compat Linux libfoo.so.1.0.0:Linux:32 - compat Linux 32
• pkg tracks 32bit compat shlibs
• pkg can track linux shlibs for linux compatibility (disabled by default) via TRACK_LINUX_COMPAT_SHLIBS