dix: add whiteroot flag

nx-X11/programs/Xserver/hw/nxagent/Init.c

@@ -413,7 +413,8 @@ FIXME: These variables, if not removed at all because have probably
    * background.
    */
 
-  blackRoot = TRUE;
+  if (!whiteRoot)
+    blackRoot = TRUE;
 
   nxagentInitKeystrokes(False);
 

nx-X11/programs/Xserver/hw/nxagent/man/nxagent.1

@@ -142,8 +142,10 @@ to authenticate access.  See also the \fIxdm\fP(1) and
 disables backing store support on all screens.
 .TP 8
 .B \-br
-sets the default root window to solid black instead of the standard root weave
-pattern.
+sets the default root window to solid black (default).
+.TP 8
+.B \-wr
+sets the default root window to solid white.
 .TP 8
 .B \-c
 turns off key-click.

nx-X11/programs/Xserver/os/utils.c

@@ -634,6 +634,7 @@ void UseMsg(void)
     ErrorF("v                      video blanking for screen-saver\n");
     ErrorF("-v                     screen-saver without video blanking\n");
     ErrorF("-wm                    WhenMapped default backing-store\n");
+    ErrorF("-wr                    create root window with white background\n");
     ErrorF("-maxbigreqsize         set maximal bigrequest size \n");
 #ifdef PANORAMIX
     ErrorF("+xinerama              Enable XINERAMA (PanoramiX) extension\n");
@@ -996,6 +997,8 @@ ProcessCommandLine(int argc, char *argv[])
 	    defaultScreenSaverBlanking = DontPreferBlanking;
 	else if ( strcmp( argv[i], "-wm") == 0)
 	    defaultBackingStore = WhenMapped;
+	else if ( strcmp( argv[i], "-wr") == 0)
+	    whiteRoot = TRUE;
         else if ( strcmp( argv[i], "-maxbigreqsize") == 0) {
              if(++i < argc) {
                  long reqSizeArg = atol(argv[i]);