int strv_extend_strv(char ***a, char **b);
int strv_extend_strv_concat(char ***a, char **b, const char *suffix);
int strv_extend(char ***l, const char *value);
+int strv_extendf(char ***l, const char *format, ...) _printf_(2,0);
int strv_push(char ***l, char *value);
int strv_consume(char ***l, char *value);