--- ray/src/util/CMakeLists.txt	2014/02/10 17:50:02	1.13
+++ ray/src/util/CMakeLists.txt	2014/03/20 22:49:21	1.14
@@ -78,7 +78,7 @@ find_file(HAVE_SGISTEREO_H "SGIStereo.h" ${OPENGL_INCL
 if(NOT HAVE_SGISTEREO_H)
 	add_definitions(-DNOSTEREO)
 endif()
-if(UNIX)
+if(UNIX AND X11_FOUND)
 	add_executable(glrad glrad.c)
 	target_link_libraries(glrad rgl rtrad ${OPENGL_LIBRARIES} ${X11_LIBRARIES})
 	install(TARGETS rpiece RUNTIME DESTINATION bin)