继续翻译
Secondary Expansion of Static Pattern Rules ------------------------------------------- Rules for secondary expansion of static pattern rules are identical to those for explicit rules, above, with one exception: for static pattern rules the `$$*' variable is set to the pattern stem. As with explicit rules, `$$?' is not available and expands to the empty string.
对静态规则的二次扩展，和对显式规则的二次扩展完全类似。但是有一个例外：
对静态规则，$$* 变量被设置为 模式 stem。$$? 无法使用于静态规则，会扩展为空串。
后文待续