All DECLAREs need to be at the top. ie.
delimiter //
CREATE TRIGGER pgl_new_user
AFTER INSERT ON users FOR EACH ROW
BEGIN
DECLARE m_user_team_id integer;
DECLARE m_projects_id integer;
DECLARE cur CURSOR FOR SELECT project_id FROM user_team_project_relationships WHERE user_team_id = m_user_team_id;
SET @m_user_team_id := (SELECT id FROM user_teams WHERE name = "pgl_reporters");
OPEN cur;
ins_loop: LOOP
FETCH cur INTO m_projects_id;
IF done THEN
LEAVE ins_loop;
END IF;
INSERT INTO users_projects (user_id, project_id, created_at, updated_at, project_access)
VALUES (NEW.id, m_projects_id, now(), now(), 20);
END LOOP;
CLOSE cur;
END//