Add GCC toolchain builder. Update README and .gitignore accordingly.
Created by: zchamski
- .gitignore: Ignore source and build subdirectories of the toolchain builder.
- README.md (Prerequisites): Update toolchain build instructions.
- util/gcc-toolchain-builder/README.md: New.
- util/gcc-toolchain-builder/build-toolchain.sh: Ditto.
- util/gcc-toolchain-builder/config/gcc-13.1.0-baremetal.sh: Ditto.
- util/gcc-toolchain-builder/config/gcc-master-baremetal.sh: Ditto.
- util/gcc-toolchain-builder/get-toolchain.sh: Ditto.