diff --git a/configure.ac b/configure.ac
index 7e1dd69..d375107 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,7 +22,6 @@ AM_PROG_CC_C_O
 
 # Checks for libraries.
 AC_CHECK_LIB([SDL],[SDL_Init],,[AC_MSG_ERROR([cannot find libsdl])])
-AC_CHECK_LIB([X11],[XOpenDisplay],,[AC_MSG_ERROR([cannot find X11])])