ssh-pull.con commit Document 'opendiff' value in config.txt and git-mergetool.txt (e4e92b3)
   1#define COUNTERPART_ENV_NAME "GIT_SSH_PUSH"
   2#define COUNTERPART_PROGRAM_NAME "git-ssh-push"
   3#define MY_PROGRAM_NAME "git-ssh-pull"
   4#include "ssh-fetch.c"