Move the function mkdirp into common to be generally available.
Use the new common.mkdirp from create_user_directory() from
core/init.lua replacing previous parent directory creation code
within the function.
The previous mkdirp function did not work on Windows where
absolute paths starts with a drive letter. The code from
create_user_directory() did not have this problem but was wrong
in the way it was creating the nested directories.
The new implementation in common.mkdirp fix both problems.
FrancescoandGitHub
98164f6d4f