Bumped GCC and binutils versions, because GDC 4.9 is (probably) significantly better than GDC 4.8
BUG FIX: GDC can't link against uClibc - changing to eglibc.
This increases the rootfs size from 22 MB to 30 MB.
BUG FIX: Github API requires the archive format to be specified
Added GDC support to Buildroot