Make sure that there is an environment variable called DEVKITARM with the path of the directory before the "bin" directory containing "arm-none-eabi-as", "arm-none-eabi-cpp", "arm-none-eabi-ld" and "arm-none-eabi-objcopy".
Then get the compiler from https://github.com/pret/agbcc and run the following commands.
Then get the compiled tools from https://github.com/pret/pokeruby-tools. Copy the `tools/` folder over the `tools/` folder in your pokeemerald directory.
If the step `./build.sh` in the above list of commands fails with the error `Makefile:1: /opt/devkitpro/devkitARM/base_tools: No such file or directory`, then try installing the pacman package `devkitarm-rules` by executing the command
`-j` on its own will spawn a new thread for each job. A clean build will have thousands of jobs, which will be slower than not using -j at all.
## Disable the dependency scanning
If you've only changed `.c` or `.s` files, you can turn off the dependency scanning temporarily. Changes to any other files will be ignored, and the build will either fail or not reflect those changes.