[staging-next] gnat-bootstrap14: fix gnat14 build on aarch64-linux (#493093)

        fi

      done

    ''

    # x86_64-darwin needs this for the reason above, and aarch64-linux needs it

    # to avoid https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118009,

    # but x86_64-linux doesn't seem to need it.

    + lib.optionalString (stdenv.hostPlatform.system != "x86_64-linux") ''

      "$out"/libexec/gcc/${upstreamTriplet}/${gccVersion}/install-tools/mkheaders -v -v \

        "$out" "${stdenv.cc.libc}"

    '';