Examples of multi-line AC_DEFINEs?

[Eric Lemings]

Greetings,
 
In section 7.1, the GNU Autoconf 2.62 Manual says, "value may contain
backslash-escaped newlines, which will be preserved if you use
AC_CONFIG_HEADERS but flattened if passed via @DEFS@ (with no effect on
the compilation, since the preprocessor sees only one line in the first
place)."
 
I was just wondering if there are some examples of such usage somewhere,
perhaps in the test suite, or elsewhere?
 
Thanks,
Eric.