Simply X11 Qt4 error detection

configure.ac

@@ -5187,9 +5187,6 @@ AS_IF([test "${enable_qt4}" != "no" &&
     [ VLC_ADD_PLUGINS([qt4])
       ALIASES="${ALIASES} qvlc"
       enableqt4=true
-      if test "${SYS}" != "mingw32" -a "${SYS}" != "mingwce" -a "${SYS}" != "cygwin"; then
-        AC_CHECK_HEADERS([X11/Xlib.h],[],[AC_MSG_ERROR([You need X11 headers])])
-      fi
       VLC_ADD_LIBS([qt4],[$QT4_LIBS])
       VLC_ADD_CXXFLAGS([qt4],[$QT4_CFLAGS -DQT4LOCALEDIR=\\\\\\\"$($PKG_CONFIG --variable=prefix QtCore)/share/qt4/translations/\\\\\\\"])
       AC_PATH_PROGS(MOC, [moc-qt4 moc], moc,`$PKG_CONFIG --variable=exec_prefix QtCore`/bin)

modules/gui/qt4/qt4.cpp

@@ -180,19 +180,13 @@ static int Open( vlc_object_t *p_this )
 {
     intf_thread_t *p_intf = (intf_thread_t *)p_this;
     p_intf->pf_run = Run;
-#if defined HAVE_GETENV && defined Q_WS_X11 && defined HAVE_X11_XLIB_H
-    char *psz_display = getenv( "DISPLAY" );
-    if( !psz_display || !*psz_display )
-    {
-        msg_Err( p_intf, "no X server" );
-        return VLC_EGENERIC;
-    }
+#if defined Q_WS_X11 && defined HAVE_X11_XLIB_H
     /* Thanks for libqt4 calling exit() in QApplication::QApplication()
-     * instead of returning an error, we have to check for DISPLAY validity */
-    Display *p_display = XOpenDisplay( psz_display );
+     * instead of returning an error, we have to check the X11 display */
+    Display *p_display = XOpenDisplay( NULL );
     if( !p_display )
     {
-        msg_Err( p_intf, "Could not connect to X server %s", psz_display );
+        msg_Err( p_intf, "Could not connect to X server" );
         return VLC_EGENERIC;
     }
     XCloseDisplay( p_display );