FreeBSD does not have a dl.so

--- src/libntirpc/tests/CMakeLists.txt.orig	2018-09-11 18:22:10 UTC
+++ src/libntirpc/tests/CMakeLists.txt
@@ -6,5 +6,4 @@ add_executable(rpcping ${rpcping_SRCS})
 target_link_libraries(rpcping ntirpc
   ${BINARY_LIBRARIES}
   ${CMAKE_THREAD_LIBS_INIT}
-  ${LTTNG_LIBRARIES}
-  -ldl)
+  ${LTTNG_LIBRARIES})
