Bug report

Bug description:

This occurs in two cases:

• Output is still generated when there is no input. Whereasxgettext:

  $ xgettextxgettext: no input file givenTry 'xgettext --help' for more information.

  And the second case follows on from this (but can also occur with input files)
• Inxgettext, no output is generated if there are no messages. Inpygettext output is still generate even if no messages are found, the header is still sent.
  We should fix it to work likexgettext and not produce "empty" output.

I will send a pr soon, once other tests are merged.

cc@tomasr8

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response