Translate SPDX licenses to Fedora license tags, warn about "/"
    
    "/" is deprecated everywhere, so warn about that.
    Translation from SPDX is only used for fedora or epel targets.
    
    The Fedora license list coalesces various license variants that have different
    SPDX license tags into a single license tag. Most notably, this is done for the
    39 BSD variants and 18 MIT variants on the Fedora good licenses list. When a
    spdx→fedora mapping exists, it should always be unambiguous, because SPDX
    considers any change in the license text to be a unique license, and Fedora is
    more permissive in that regard.
    
    To make a review of the translation easy, debug info is output to stdout, and
    comments are inserted into the spec when some translation is required or when
    there are problems with the upstream licensing.
    
    The license list is pulled from the spdx project:
    $ curl 'https://docs.google.com/spreadsheets/d/1LUJuzGKC5K2yYuAg8S-2VYbS2dmg_4IlFdpqj7n9Ghg/export?format=csv&id=1LUJuzGKC5K2yYuAg8S-2VYbS2dmg_4IlFdpqj7n9Ghg&gid=138634715' > rust2rpm/spdx_to_fedora.csv
    
    v2:
    - apply "/" replacement always
    
    v3:
    - print to stderr
    - use csv.DictReader
    - filter out empty license lines