RISC-V Toolchain 
This provides packages to install the RISC-V toolchain on OS X using Homebrew.
Installation
First, install homebrew:
$ ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"
Get this tap:
$ brew tap riscv/riscv
Build the toolchain:
$ brew install riscv-tools
If you have macOS Sierra (10.12) or High Sierra (10.13), riscv-tools will be installed from precompiled binaries. If you do not have Sierra, riscv-tools will be built from source. It builds with the default compiler (clang), but you can specify another compiler on the command line. For example:
$ brew install --cc=gcc-5 riscv-tools
Testing
You can verify your install was successful by:
$ brew test riscv-tools
This will compile and run a hello world, so it will use all of the components (riscv-fesvr, riscv-isa-sim, riscv-pk, and riscv-gnu-toolchain).
Updating
To pull in the latest version of a package, you can force an install and compile it yourself by:
$ brew reinstall --build-from-source riscv-fesvr