devel/freebsd-gcc6: Retire obsolete port.
Supported FreeBSD versions can no longer be built with GCC 6 and
users wishing to compile FreeBSD with GCC are encouraged to use
devel/freebsd-gcc9 or devel/freebsd-gcc12 instead.
Reviewed by: manu, otis
Differential Revision: https://reviews.freebsd.org/D39218
Don't disable LTO for aarch64-gcc.
aarch64-binutils is no longer built static by default, so aarch64-gcc
can now enable LTO.
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D25783
Rename base/gcc to base/gcc6.
This is in preparation for adding a base/gcc9 port.
While here, update to GCC 6.5.0.
Share packing lists with the freebsd-gcc6 port as much as posible.
Split most of the freebsd-gcc6 pkg-plist into a pkg-plist.common that
lists arch-independent files under lib/. Change base/gcc6 to use the
arch-specific packing lists and pkg-list.common from freebsd-gcc6. In
addition, hook up packing lists for the remaining archs supported by
freebsd-gcc6 but not base/gcc6: aarch64 and sparc64.
Reviewed by: bapt
Differential Revision: https://reviews.freebsd.org/D22900