diff -urp mathgl-2.3.5.1/CMakeLists.txt mathgl-2.3.5.1-fltk-skip-fluid/CMakeLists.txt
--- mathgl-2.3.5.1/CMakeLists.txt	2016-12-27 09:44:48.138478382 +0700
+++ mathgl-2.3.5.1-fltk-skip-fluid/CMakeLists.txt	2016-12-27 10:01:05.130484991 +0700
@@ -515,6 +515,7 @@ endif(enable-glut)
 
 if(enable-fltk)
 	set(MGL_HAVE_FLTK 1)
+	set(FLTK_SKIP_FLUID 1)
 	include(FindFLTK)
 	if(NOT FLTK_FOUND)
 		message(SEND_ERROR "Couldn't find FLTK library.")