diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b98c8b4..50f568d 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -18,6 +18,8 @@ include_directories(
 
 set(EXTRA_LIBS ${LIBEV_LIBRARY} m)
 
+include(CheckLibraryExists)
+
 check_library_exists(dl dlopen "" HAVE_DLOPEN)
 if(HAVE_DLOPEN)
     list(APPEND EXTRA_LIBS dl)