Add .editorconfig

[lnussel]

No description provided.

[laenion]

The file https://github.com/openSUSE/transactional-update/blob/master/sbin/transactional-update.in has a more complicated indentation style: It's 4 spaces, followed by 1 tabs (taking up 8 spaces), followed by 1 tab 4 spaces etc. From what I can see this is not supported by EditorConfig?

[lnussel]

that is what the config sets. Ie sw=4 ts=8

[laenion]

I see - the website seems to be a bit misleading (or leaving out information). https://editorconfig-specification.readthedocs.io/#supported-pairs suggests that this may work, while https://editorconfig.org/#file-format-details just claims that indent_size will be used when indent_style is set to tab - implying that tab-width wouldn't be used. I guess you tested this with some editor already?

Apart from that: I think another header

[*/Makefile.am]

is required for correct tab indentation in those files.