digest: add direct distinfo support?

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

On the topic of grafana again... if we improved digest so that it
directly parsed a distinfo file and checked the files itself, would
that be enough for 'make checksum'?

Something like:

	  cd /usr/pkgsrc/category/package
	  digest -d distinfo -D /usr/pkgsrc/distfiles

to check all files in the distinfo, or perhaps

	  digest -d distinfo -D /usr/pkgsrc/distfiles -F /tmp/filelist.XXXX

to check only the files listed in /tmp/filelist.XXXX.

This doesn't look too difficult and would probably be much faster what
we have now. And digest is already a tool on every pkgsrc platform, so
no higher difficulty in bootstrapping.

Would that work or am I overlooking something?

(I have no similar plan yet for 'make mdi', but one step at a time.)
 Thomas