changed linker flag so builds will complete on test machines

Author: benjaminlarson

src/CMakeLists.txt

@@ -188,7 +188,7 @@ IF(UNIX)
 
   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXX_LANGUAGE_STANDARD_FLAG} -Wall")
   IF(NOT APPLE)
-    SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -lrt")
+    SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--no-as-needed -ldl")
   ENDIF()
 ENDIF()