The source project of this merge request has been removed.
Riscv64gc support in the build scripts
This architecture is different from x86/aarch because its rust triplet (riscv64gc-...) differs from gcc/llvm/binutils triplet (more general riscv64-...). Therefore the build scripts have to bridge that mismatch.
This introduces new build-time environment variable GNU_TARGET which corresponds to a target used by C world utilities whereas existing TARGET now describes rust target.