This will give you a button to do this automatically. Requires password.
It looks like SteamOS lacks some headers of of the box.
You need to add them for this to work.
# 1. Disable SteamOS read-only filesystem mode
sudo steamos-readonly disable
# 2. Initialize and populate pacman keyrings
sudo pacman-key --init
sudo pacman-key --populate archlinux holoiso
# 3. Update repositories and install essential build tools
sudo pacman -Sy base-devel glibc linux-api-headers gcc
After that it should run.