Update to 4.39:
    - Automatic creation of subdirectories of auxdir
    - Add error diagnostics to if_source
    - Allow print_type = 'auto'
    - Fix use of directories with names containing perl glob characters
    - Ensure that subdirectories are created properly
    - In output of dependencies, include pathname of target file(s) in the rule.
    - In -pvc mode, writing of deps file is per make not per overall run.