Buildroot vs RISC-V GNU Toolchain

Buildroot has no write-up on Specifiction yet; its figures are above.

RISC-V GNU Toolchain is a C and C++ cross-compiler for building bare-metal ELF or Linux ELF toolchains. It supports RV32 and RV64 targets, with RV64GC as the default, and lets builders select architecture extensions and ABIs. Bare-metal configurations can use Newlib or Picolibc; Linux configurations can use glibc, musl, or uClibc. Multilib builds can target 32-bit and 64-bit systems for Newlib and Linux/glibc toolchains. The toolchain includes GCC, binutils, GDB, and supported libraries. LLVM can be built alongside it using a configure option, though that option cannot be combined with multilib settings. The project documents testing with DejaGNU and make check targets, plus QEMU, GDB, and experimental Spike simulator options whose availability varies by toolchain. Hosts include Linux and macOS; Windows use is through a Linux subsystem or Cygwin. A build needs about 8 GiB of disk space, and cloning takes around 6.65 GB. It is free and open-source, with development material aimed at developers and advanced users.