winex11: Add registry option to let wine decorate windows.

dlls/winex11.drv/window.c

@@ -148,6 +148,8 @@ static unsigned long get_mwm_decorations( DWORD style, DWORD ex_style )
 {
     unsigned long ret = 0;
 
+    if (!decorated_mode) return ret;
+
     if (ex_style & WS_EX_TOOLWINDOW) return 0;
 
     if ((style & WS_CAPTION) == WS_CAPTION)

dlls/winex11.drv/x11drv.h

@@ -548,6 +548,7 @@ extern int use_xkb;
 extern int use_take_focus;
 extern int use_primary_selection;
 extern int managed_mode;
+extern int decorated_mode;
 extern int private_color_map;
 extern int primary_monitor;
 extern int copy_default_colors;

dlls/winex11.drv/x11drv_main.c

@@ -82,6 +82,7 @@ int use_xkb = 1;
 int use_take_focus = 1;
 int use_primary_selection = 0;
 int managed_mode = 1;
+int decorated_mode = 1;
 int private_color_map = 0;
 int primary_monitor = 0;
 int client_side_with_core = 1;
@@ -360,6 +361,9 @@ static void setup_options(void)
     if (!get_config_key( hkey, appkey, "Managed", buffer, sizeof(buffer) ))
         managed_mode = IS_OPTION_TRUE( buffer[0] );
 
+    if (!get_config_key( hkey, appkey, "Decorated", buffer, sizeof(buffer) ))
+        decorated_mode = IS_OPTION_TRUE( buffer[0] );
+
     if (!get_config_key( hkey, appkey, "DXGrab", buffer, sizeof(buffer) ))
         dxgrab = IS_OPTION_TRUE( buffer[0] );