Backwards compatibility. Andy and Bill made me add socket library.

Modules/FindX11.cmake

@@ -12,6 +12,7 @@ IF (UNIX)
   SET(CMAKE_X_PRE_LIBS "")
   SET(CMAKE_X_REAL_LIBS "")
   SET(CMAKE_X_EXTRA_LIBS "")
+  SET(CMAKE_X_EXTRA_LIBS "")
   SET(CMAKE_HAS_X 0)
   
   FIND_PATH(CMAKE_X11_INCLUDE_PATH X11/X.h
@@ -87,6 +88,11 @@ IF (UNIX)
     ENDIF(CMAKE_X_LIBS)
   ENDIF(CMAKE_X11_INCLUDE_PATH)
   IF(CMAKE_HAS_X)
+    INCLUDE (${CMAKE_ROOT}/Modules/CheckLibraryExists.cmake)
+    CHECK_LIBRARY_EXISTS("socket" "connect" "" CMAKE_HAVE_SOCKET_LIBRARY)
+    IF (CMAKE_HAVE_SOCKET_LIBRARY)
+      SET (CMAKE_X_EXTRA_LIBS "${CMAKE_X_EXTRA_LIBS};-lsocket")
+    ENDIF (CMAKE_HAVE_SOCKET_LIBRARY)
     SET (CMAKE_X_LIBS "${CMAKE_X_PRE_LIBS};${CMAKE_X_LIBS};${CMAKE_X_EXTRA_LIBS}" 
          CACHE STRING 
          "Libraries and options used in X11 programs.")
@@ -102,4 +108,5 @@ IF (UNIX)
     CMAKE_Xlib_INCLUDE_PATH
     CMAKE_Xutil_INCLUDE_PATH
     )
+
 ENDIF (UNIX)