configure.ac: add check for setns()

When compiling with upstream support (i.e. --with-cgroup), we also
need setns() function. On some platforms (RHEL6) libcgroup is available
but setns() is not. Bail out sooner in this case.

Signed-off-by: Kir Kolyshkin <kir@openvz.org>
1 file changed