Fixed undefined references to joystick code

configure.in

@@ -2916,8 +2916,8 @@ esac
 
 # Verify that we have all the platform specific files we need
 
-if test x$enable_joystick = xyes; then
-    if test x$have_joystick != xyes; then
+if test x$have_joystick != xyes; then
+    if test x$enable_joystick = xyes; then
         AC_DEFINE(SDL_JOYSTICK_DISABLED)
     fi
     SOURCES="$SOURCES $srcdir/src/joystick/dummy/*.c"

src/joystick/dummy/SDL_sysjoystick.c

@@ -87,4 +87,5 @@ SDL_SYS_JoystickQuit(void)
 }
 
 #endif /* SDL_JOYSTICK_DUMMY || SDL_JOYSTICK_DISABLED */
+
 /* vi: set ts=4 sw=4 expandtab: */