--tool=<tool>::
Use the merge resolution program specified by <tool>.
Valid merge tools are:
- kdiff3, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff, ecmerge,
- diffuse, tortoisemerge, opendiff, p4merge and araxis.
+ araxis, bc3, diffuse, ecmerge, emerge, gvimdiff, kdiff3,
+ meld, opendiff, p4merge, tkdiff, tortoisemerge, vimdiff and xxdiff.
+
If a merge resolution program is not specified, 'git mergetool'
will use the configuration variable `merge.tool`. If the