ci/build.sh: Enable CI for riscv32gc-unknown-linux-gnu
ci/build.sh: Enable CI for riscv32gc-unknown-linux-gnu

Signed-off-by: Alistair Francis <52ecf00b70a50079ae8d5fa09b9af6904950b63c@wdc.com>

rust-lang/libc,rust-lang/libc,rust-lang/libc