Merge branch 'js/patch-mode-in-others-in-c' into jch

The effort to move "git-add--interactive" to C continues.

* js/patch-mode-in-others-in-c:
  commit --interactive: make it work with the built-in `add -i`
  built-in add -p: implement the "worktree" patch modes
  built-in add -p: implement the "checkout" patch modes
  built-in stash: use the built-in `git add -p` if so configured
  legacy stash -p: respect the add.interactive.usebuiltin setting
  built-in add -p: implement the "stash" and "reset" patch modes
  built-in add -p: prepare for patch modes other than "stage"

add-interactive.c

@@ -924,7 +924,7 @@ static int run_patch(struct add_i_state *s, const struct pathspec *ps,
 		parse_pathspec(&ps_selected,
 			       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
 			       PATHSPEC_LITERAL_PATH, "", args.argv);
-		res = run_add_p(s->r, &ps_selected);
+		res = run_add_p(s->r, ADD_P_ADD, NULL, &ps_selected);
 		argv_array_clear(&args);
 		clear_pathspec(&ps_selected);
 	}

add-interactive.h

@@ -22,6 +22,16 @@ void init_add_i_state(struct add_i_state *s, struct repository *r);
 struct repository;
 struct pathspec;
 int run_add_i(struct repository *r, const struct pathspec *ps);
-int run_add_p(struct repository *r, const struct pathspec *ps);
+
+enum add_p_mode {
+	ADD_P_ADD,
+	ADD_P_STASH,
+	ADD_P_RESET,
+	ADD_P_CHECKOUT,
+	ADD_P_WORKTREE,
+};
+
+int run_add_p(struct repository *r, enum add_p_mode mode,
+	      const char *revision, const struct pathspec *ps);
 
 #endif