v4.0.0

Changes

• Remove -v option, your package manager of choice can already provide the
  same information
  (2905675)
  (Anton Lindqvist)

• Remove -h option in favor of the manual.
  (93a552b)
  (Anton Lindqvist)

• Do not output options as part of the usage output, in favor of the manual
  instead.
  (e253d7d)
  (Anton Lindqvist)

Bug fixes

• Mark unused variables in compat files as extern in order to compile using
  GCC 10.
  (160d7be)
  (Benjamin Porter)