diff --git a/CMakeLists.txt b/CMakeLists.txt
index ab8f60c782..c14c24816f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -241,6 +241,7 @@ else()
 	endif()
 
 	if ( UNIX )
+		include(CheckSymbolExists)
 		check_symbol_exists( "fts_set" "fts.h" HAVE_FTS )
 		if ( NOT HAVE_FTS )
 			include ( FindPkgConfig )