Detected BSD in CMakeList

CMakeLists.txt

@@ -28,6 +28,8 @@ elseif(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
     LIST(APPEND LIBS "m")
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "NetBSD")
     LIST(APPEND LIBS "m")
+elseif(${CMAKE_SYSTEM_NAME} MATCHES "BSD|DragonFly")
+    LIST(APPEND LIBS "m")
 elseif(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
     LIST(APPEND LIBS "m" "rt")
 endif()