继续翻译
`%' characters in a `vpath' directive's pattern can be quoted with preceding backslashes (`\'). Backslashes that would otherwise quote `%' characters can be quoted with more backslashes. Backslashes that quote `%' characters or other backslashes are removed from the pattern before it is compared to file names. Backslashes that are not in danger of quoting `%' characters go unmolested.
When a prerequisite fails to exist in the current directory, if the PATTERN in a `vpath' directive matches the name of the prerequisite file, then the DIRECTORIES in that directive are searched just like(and before) the directories in the `VPATH' variable. For example, vpath %.h ../headers tells `make' to look for any prerequisite whose name ends in `.h' in the directory `../headers' if the file is not found in the current directory.
在一个 vpath 指令模式中的 % 符号可以被反斜线引用起来。反斜线也可以被反斜线所引用。
在进行文件名比较的时候，起到引用作用的反斜线将被从模式中移走。不起引用作用的反斜线会被忽略。
一个前提条件不在当前目录，如果 vpath 指令中的模式匹配了前提条件文件，那么此指令中的 DIRECTORIES 就会被搜索，就像在 VPATH 变量中一样。
例如，
vpath %.h ../headers
告诉 make 去在 ../headers 目录下寻找任何名字为 .h 的文件，如果此文件在当前目录中没有的话。
后文待续