Before the change separate-debug-info.sh did the stripping itself.
This scheme has a few problems:
1. Stripping happens only on ELF files. *.a and *.o files are skipped.
Derivations have to do it manually. Usually incorrectly
as they don't run $RANLIB (true for `glibc` and `musl`).
2. Stripping happens on all paths. Ideally only `stripDebugList` paths
should be considered.
3. Host strip is called on Target files.
This change offloads stripping logic to strip hook. This strips more
files for `glibc` and `musl`. Now we can remove most $STRIP calls
from individual derivations.
Co-authored-by: Sandro <sandro.jaeckel@gmail.com>
