On behalf of: Ludovic Henry (ludovic@rivosinc.com)

The current build is still using the same binutils src folder to build multiple architectures, meaning there will be a conflict when cross-compiling and/or native-compiling.
The change[1] used the folder `build/<target>/binutils` as the build folder for binutils, so that the binutils source tree stays clean and can be used for multiple targets.

[1] https://github.com/rivosinc/jdk/commit/4c88e66b654e4c29ede7c221d223298497fa06c2