Ibacm: Check the presence of header files for netlink support
It was found that the latest ibacm will not build in old distros that
don't have the two header files rdma/rdma_netlink.h and rdma/ib_user_sa.h.
To be backward compatible, the netlink support should be disabled if
the header files were absent. This patch will address the issue.
Reported-by: Hal Rosenstock <hal@mellanox.com> Signed-off-by: Kaike Wan <kaike.wan@intel.com> Signed-off-by: Sean Hefty <sean.hefty@intel.com>