[ install ] Fix `install-libdocs` makefile target
[ install ] Fix `install-libdocs` makefile target

On some systems, `/bin/sh` is a symlink to a minimal shell (e.g. `dash`) that doesn't understand bashisms like `mkdir -p some_dir/{one,two,three}`.

mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm