// Find the child that matches the first part of 'path'.
// E.g. if a child path is "/usr" and 'path' is "/usr/include"
// then the child for /usr is returned.
// If the path string has been used (we're at the leaf), done is set to TRUE
// Find the child that matches the first part of 'path'.
// E.g. if a child path is "/usr" and 'path' is "/usr/include"
// then the child for /usr is returned.
// If the path string has been used (we're at the leaf), done is set to TRUE