Merge branch 'jc/strbuf-getline'

The preliminary clean-up for jc/peace-with-crlf topic. * jc/strbuf-getline: strbuf: give strbuf_getline() to the "most text friendly" variant checkout-index: there are only two possible line terminations update-index: there are only two possible line terminations check-ignore: there are only two possible line terminations check-attr: there are only two possible line terminations mktree: there are only two possible line terminations strbuf: introduce strbuf_getline_{lf,nul}() strbuf: make strbuf_getline_crlf() global strbuf: miniscule style fix