Build: use ccache and gold if available
Build: use ccache and gold if available

Gold is an alternative linker part of the gnu project. It's faster than
ld, around three time faster.

ccache is a compiler cache that speedup rebuild.

xlqian/navitia,Tisseo/navitia,CanalTP/navitia,pbougue/navitia,CanalTP/navitia,CanalTP/navitia,pbougue/navitia,pbougue/navitia,xlqian/navitia,CanalTP/navitia,Tisseo/navitia,pbougue/navitia,xlqian/navitia,xlqian/navitia,Tisseo/navitia,kinnou02/navitia,kinnou02/navitia,kinnou02/navitia,CanalTP/navitia,Tisseo/navitia,xlqian/navitia,kinnou02/navitia,Tisseo/navitia