--- fltk1.1-1.1.10.orig/src/Makefile
+++ fltk1.1-1.1.10/src/Makefile
@@ -210,13 +210,13 @@
 
 libfltk.so.1.1: $(OBJECTS)
 	echo $(DSOCOMMAND) $@ ...
-	$(DSOCOMMAND) $@ $(OBJECTS)
+	$(DSOCOMMAND) $@ $(OBJECTS) $(LDLIBS) -lpthread
 	$(RM) libfltk.so
 	$(LN) libfltk.so.1.1 libfltk.so
 
 libfltk.sl.1.1: $(OBJECTS)
 	echo $(DSOCOMMAND) $@ ...
-	$(DSOCOMMAND) $@ $(OBJECTS)
+	$(DSOCOMMAND) $@ $(OBJECTS) $(LDLIBS)
 	$(RM) libfltk.sl
 	$(LN) libfltk.sl.1.1 libfltk.sl
 
@@ -282,13 +282,13 @@
 
 libfltk_gl.so.1.1: $(GLOBJECTS) libfltk.so.1.1
 	echo $(DSOCOMMAND) $@ ...
-	$(DSOCOMMAND) $@ $(GLOBJECTS) -L. -lfltk
+	$(DSOCOMMAND) $@ $(GLOBJECTS) -lGL -lX11 -ldl -L. -lfltk
 	$(RM) libfltk_gl.so
 	$(LN) libfltk_gl.so.1.1 libfltk_gl.so
 
 libfltk_gl.sl.1.1: $(GLOBJECTS) libfltk.sl.1.1
 	echo $(DSOCOMMAND) $@ ...
-	$(DSOCOMMAND) $@ $(GLOBJECTS) -L. -lfltk
+	$(DSOCOMMAND) $@ $(GLOBJECTS) -lGL -lX11 -ldl -L. -lfltk
 	$(RM) libfltk_gl.sl
 	$(LN) libfltk_gl.sl.1.1 libfltk_gl.sl