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
New cross build ready version of gcc.
This port is special, it is done only for being cross build and prepare a modern
compiler for base system build without a cross compiler
It contains the printf format extension needed for the kernel as only patch for
It uses libc++ from base as a standard c++ library default on the libc++ headers
as c++ headers