ignore first damage for X clients

when not dealing with a re_manage client (persisting from previous E instance), we're almost definitely going to get multiple full-window damages as a new client starts up. the first damage USUALLY results in a garbage render, so ignoring it makes the first frame become actual window content (good!) or a transparent rect until the client finishes drawing (not good!), which is at least an improvement over showing random pixels

src/bin/e_comp_x.c

@@ -2453,6 +2453,12 @@ _e_comp_x_damage(void *data EINA_UNUSED, int type EINA_UNUSED, Ecore_X_Event_Dam
         ecore_x_damage_subtract(ec->comp_data->damage, 0, parts);
         ecore_x_region_free(parts);
      }
+   if (!ec->comp_data->first_damage)
+     {
+        ec->comp_data->first_damage = 1;
+        if (!ec->re_manage)
+          return ECORE_CALLBACK_RENEW;
+     }
 
    //WRN("DAMAGE %p: %dx%d", ec, ev->area.width, ev->area.height);
    if (ec->comp->nocomp)

src/bin/e_comp_x.h

@@ -31,13 +31,13 @@ struct _E_Comp_Client_Data
    Ecore_X_Sync_Alarm   alarm;
    Ecore_X_Sync_Counter sync_counter;  // netwm sync counter
 
-   unsigned char        misses; // number of sync misses
-
    Ecore_X_Window_Attributes initial_attributes;
 
    unsigned int move_counter; //reduce X calls when moving a window
    unsigned int internal_props_set; //don't need to refetch our own internal props
 
+   Eina_Bool first_damage : 1; //ignore first damage on non-re_manage clients
+
    struct
    {
       struct