You're supposed to have librdmacm installed as part of
MLNX_OFED installation.
What does "rpm -qa | grep rdma" tell?
$ rpm -qa | grep rdma
librdmacm-devel-1.0.14.1-1.x86_64
librdmacm-utils-1.0.14.1-1.x86_64
librdmacm-1.0.14.1-1.x86_64
$ locate
librdmacm.la
/usr/local/mofed/1.5.3-4.0.9/lib/
librdmacm.la
-- YK