A recent discussion on -current about the default keys for mergemaster suggests that people find using 'l' and 'r' inconvenient. I think '1' and '2' are likely to be more reasonable even on foreign keyboard layouts, and have updated the default behavior to reflect this. The following patch also lets one define an SDIFF_MERGE_KEYS environment variable to pick any pair of keys they prefer.
How-To-Repeat: N/A--see mailing lists for prior discussion.
[ Note that my PR mail bounced, so I'm posting this via WWW form. Sorry if this mangles tabs and spaces in the diff in the next section, original copy is at: http://www.pkix.net/~chuck/sdiff.diff ]
As of FreeBSD 11, GNU sdiff has been replaced with a "permissively licensed" version so it doesn't make much sense to add features to the GNU version that may be missed in the newer version.