Adding gcc-7 as the compiler.
Adding gcc-7 as the compiler.

Signed-off-by: Tim 'mithro' Ansell <b1c1d8736f20db3fb6c1c66bb1455ed43909f0d8@mith.ro>

chipsalliance/Surelog,alainmarcel/Surelog,chipsalliance/Surelog,chipsalliance/Surelog,alainmarcel/Surelog,alainmarcel/Surelog,chipsalliance/Surelog,alainmarcel/Surelog