Merge branch 'en/merge-ort-api-null-impl'

Preparation for a new merge strategy.

* en/merge-ort-api-null-impl:
  merge,rebase,revert: select ort or recursive by config or environment
  fast-rebase: demonstrate merge-ort's API via new test-tool command
  merge-ort-wrappers: new convience wrappers to mimic the old merge API
  merge-ort: barebones API of new merge strategy with empty implementation

diff --cc Makefile
Simple merge

diff --cc builtin/merge.c
Simple merge

diff --cc builtin/rebase.c
Simple merge

diff --cc builtin/revert.c
Simple merge

diff --cc sequencer.c
index 3dce6c963cec91e6b69de360d931a7d9e294db07,6b6c15c35724d50b5296ea01806819788427c545..221e98721d23b398c115b3ae743cdc889d81515f
--- 1/sequencer.c
--- 2/sequencer.c
+++ b/sequencer.c
@@@ -314,7 -329,10 +329,8 @@@ int sequencer_remove_state(struct repla
                }
        }
  
 -      free(opts->committer_name);
 -      free(opts->committer_email);
        free(opts->gpg_sign);
+       free(opts->default_strategy);
        free(opts->strategy);
        for (i = 0; i < opts->xopts_nr; i++)
                free(opts->xopts[i]);

diff --cc sequencer.h
Simple merge

diff --cc t/helper/test-tool.c
Simple merge

diff --cc t/helper/test-tool.h
Simple merge