eo: add a EO_DEBUG environment variable to get some useful statistic.

src/lib/eo/eo.c

@@ -1062,6 +1062,13 @@ eo_class_new(const Eo_Class_Description *desc, const Eo_Class *parent, ...)
 
    _eo_class_constructor(klass);
 
+   if (getenv("EO_DEBUG"))
+     {
+        fprintf(stderr, "Eo class '%s' will take %i octets per object.\n",
+                desc->name,
+                klass->data_offset + EO_ALIGN_SIZE(klass->desc->data_size) + klass->extn_data_size);
+     }
+
    va_end(p_list);
 
    return klass;