missing sigev_notify_function from signal.h

Quoting http://pubs.opengroup.org/onlinepubs/000095399/basedefs/signal.h.html:
"The <signal.h> header shall define the sigevent structure, which has at least
the following members:

int sigev_notify Notification type.
int sigev_signo Signal number.
union sigval sigev_value Signal value.
void(*)(union sigval) sigev_notify_function Notification function. "

sigev_notify_function is missing in the LSB headers.

My workaround is to add this:
#define sigev_notify_function _sigev_un._sigev_thread._function

This is needed to build OCaml (ocaml.org).