Merge commit 'mingw/master' into devel

Conflicts:

	Makefile
	RelNotes
	compat/qsort.c
	help.c
	read-cache.c

setup.c

@@ -413,6 +413,8 @@ int check_repository_format_version(const char *var, const char *value)
 		if (is_bare_repository_cfg == 1)
 			inside_work_tree = -1;
 	} else if (strcmp(var, "core.worktree") == 0) {
+		if (!value)
+			return config_error_nonbool(var);
 		if (git_work_tree_cfg)
 			free(git_work_tree_cfg);
 		git_work_tree_cfg = xstrdup(value);