Making a separate C file prevents you from having to recompile the single-header lib every time a change is made to the file with the IMPL in it. Also compilat

Making a separate C file prevents you from having to recompile the single-header lib every time a change is made to the file with the IMPL in it. Also compilation of a single file is a lot worse when it's really big, compared to several smaller files that can use multiple cores.