problem with CLOCK_* in linux

[joseph canou <Joseph.Canou@bourges.univ-orleans.fr>]

hello
I use rtl 3pre9 with a 2.2.17 kernel
I have a problem with the different constant clock like CLOCK_REALTIME
with clock function like clock_gettime().
I don't have this problem when I compile some module for rtlinux using
CLOCK_*
when I compile for clock_gettime(CLOCK_REALTIME) in linux I have this
message:

 `CLOCK_REALTIME' undeclared (first use in this function)
 I have included time.h
I don't find the CLOCK_REALTIME in any time.h excepted in rtl_time.h but
it is an extern declaration
what must I do to solve my problem?
thank you