--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -2,7 +2,7 @@
            -DDATADIR=\""$(datadir)/lucidlife"\" \
            -DDOCDIR=\""$(datadir)/doc/lucidlife"\"
 
-LIBS = $(GNOME_LIBS)
+LIBS = $(GNOME_LIBS) -lX11
 
 bin_PROGRAMS = lucidlife