message: Provide a fallback git date and version.
  If git is not available and the GIT_DATE and GIT_VERSION
  environment variables are not set, fall back to a
  generic string.
  Fixes
diff: @@ -39,10 +39,16 @@ def main():
  version = ""
  if not date:
  + try:
  date = os.environ["GIT_DATE"]
  + except:
  + date = "<unknown-git-date>"
  if not version:
  + try:
  version = os.environ["GIT_VERSION"]
  + except:
  + version = "<unknown-git-version>"
  print("GIT_DATE", '"{}"'.format(date))
  print("GIT_DESCRIBE", '"{}"'.format(version))
  