about-filter flexibility

[Jason A. Donenfeld]

Hi folks,

I'm working on a set of patches that will make the about-filter a bit
more dynamic. One step in this is letting the about-filter know the
name of the file it is about to filter, so that it can choose the
proper sub-filterer by itself.

Currently the source-filter has this functionality by passing the
filename as argv[1] to the source-filter. This works well and is
implemented cleanly.

I'd like to do the same with about-filter, but I realize it might
break existing scripts that have differing behavior based on whether
or not argv[1] is specified. An alternative option would be to pass
the filename as an environment variable, CGIT_ABOUT_FILE, but this
then makes the filter interface follow an inconsistent scheme, which
isn't great. I'm leaning toward going with the argv[1] option, to
maintain parity with source-filter, but I wanted to solicit some
feedback before I make potentially disruptive changes.

So, let me know what you think and your argv usage of about-filter scripts.

Thanks,
Jason