poll: Follow up to r1897521: Clarify what APR_POLLEXCL means.
This is to avoid the thundering herd issue when multiple threads/processes
poll on the same descriptor (usually listening/to-be-accept()ed descriptors).
@@ -52,7 +52,7 @@ extern "C" {
#define APR_POLLERR 0x010 /**< Pending error */
#define APR_POLLHUP 0x020 /**< Hangup occurred */
#define APR_POLLNVAL 0x040 /**< Descriptor invalid */
-#define APR_POLLEXCL 0x080 /**< Exclusive */
+#define APR_POLLEXCL 0x080 /**< Exclusive wake up */
/** @} */
/**
