You need to provide low-level build functions, which is quite some work. On top of that you need to understand the build system of the libcs to replicate it. On

You need to provide low-level build functions, which is quite some work. On top of that you need to understand the build system of the libcs to replicate it. On top of that for libcs you want to deduplicate all symbols to reduce as much space as possible. On top of that you might want to provide glibc symbol versioning. People without incentive usually do not do this tedious kind of work, since "it works for me".