bindgen --version unintuitively requires an input file for no apparent reason

[pmj]

bindgen --help says:

…
  -V, --version
          Prints the version, and exits
…

But when I run it, I get:

$ bindgen --version          
error: the following required arguments were not provided:
  <HEADER>

Usage: bindgen <FLAGS> <OPTIONS> <HEADER> -- <CLANG_ARGS>...

For more information, try '--help'.

As it turns out, I really do have to specify an input file as well:

% bindgen -V mycrate/src/defs.h 
bindgen 0.71.0

This seems a really odd and confusing requirement.

[ojeda]

Duplicate of #3039.

The file does not need to exist, so an easier workaround is to pass a dummy argument, see #3039 (comment).