bash – 如何在autoconf / m4中转义文本？

我的configuration.ac文件中的以下代码不起作用(请注意嵌套方括号[default = no])：

AC_ARG_ENABLE(debug,[  --enable-debug          build with debugging support [default=no].],[DEBUG="$enableval"],[DEBUG="no"]
)

我怎么能逃脱这些括号？

找到了！从 this教程：

M4 arguments are quoted with [ and ]. There is NO WAY to escape these,however,you have several options if you wish to insert [‘s or ]’s:

1. Use a `Quadrigaph’. @<:@ gives you [ and @:>@ gives you ].
2. Balance your quotes. M4 will turn [[]] in to []. Beware of using this in arguments to macros. Sometimes,you need to double quote as well ([[[]]]).
3. Change the quoting using: changequote(<<,>>) to change the quoting to << and >>. The autoconf documentation (rightly,in my opinion) warns against the (over) use of this,since it can lead to unexpected results.
4. Avoid [ and ] where ever possible. This is my personal choice.

因此,我的新代码是：

AC_ARG_ENABLE(debug,AS_HELP_STRING(
        [--enable-debug],[build with debugging symbols @<:@default=no@:>@]),[enable_debug="$enableval"],[enable_debug="no"]
)