diff -rupN qsynth-0.3.5.old/CMakeLists.txt qsynth-0.3.5/CMakeLists.txt
--- qsynth-0.3.5.old/CMakeLists.txt	2010-04-10 11:57:19.000000000 -0400
+++ qsynth-0.3.5/CMakeLists.txt	2010-05-09 16:48:00.000000000 -0400
@@ -50,6 +50,9 @@ endif (MATH_LIBRARY)
 # Check for fluidsynth library.
 find_library ( FLUIDSYNTH_LIBRARY fluidsynth ) 
 
+# Check for X11 library.
+find_library ( X11_LIBRARY X11 )
+
 # Checks for header files.
 check_include_files ("fcntl.h;unistd.h;signal.h" HAVE_SIGNAL_H)
 
diff -rupN qsynth-0.3.5.old/src/CMakeLists.txt qsynth-0.3.5/src/CMakeLists.txt
--- qsynth-0.3.5.old/src/CMakeLists.txt	2010-05-09 16:38:53.000000000 -0400
+++ qsynth-0.3.5/src/CMakeLists.txt	2010-05-09 16:48:24.000000000 -0400
@@ -102,6 +102,7 @@ target_link_libraries ( qsynth
     ${QT_LIBRARIES}
     ${MATH_LIBRARY}
     ${FLUIDSYNTH_LIBRARY}
+    ${X11_LIBRARY}
 )
 
 set ( TRANSLATIONS