ntdll: Add SDL video driver variables to the special variables list.

Overriding the SDL_VIDEODRIVER variable (for Wayland support as an example)
on the Linux side can lead to some games under Wine failing to load (so treat
that variable as special).

dlls/ntdll/unix/env.c

@@ -341,6 +341,8 @@ static BOOL is_special_env_var( const char *var )
             STARTS_WITH( var, "TEMP=" ) ||
             STARTS_WITH( var, "TMP=" ) ||
             STARTS_WITH( var, "QT_" ) ||
+            STARTS_WITH( var, "SDL_VIDEODRIVER=" ) ||
+            STARTS_WITH( var, "SDL_VIDEO_DRIVER=" ) ||
             STARTS_WITH( var, "VK_" ) ||
             STARTS_WITH( var, "XDG_SESSION_TYPE=" ));
 }