eina: force copy of not copied virtualized file while doing an eina_file_dup.

The other way around is pretty much impossible as you don't know who does
an eina_file_dup and for how long they keep there reference.

T5234

src/lib/eina/eina_file_common.c

@@ -477,6 +477,19 @@ eina_file_dup(const Eina_File *f)
      {
         EINA_FILE_MAGIC_CHECK(f, NULL);
         eina_lock_take(&file->lock);
+        if (file->virtual)
+          {
+             // For ease of use and safety of the API, if you dup a virtualized file, we prefer to make a copy
+             if (file->global_map != (void*)(file->filename + strlen(file->filename) + 1))
+               {
+                  Eina_File *r;
+
+                  r = eina_file_virtualize(file->filename, file->global_map, file->length, EINA_TRUE);
+                  eina_lock_release(&file->lock);
+
+                  return r;
+               }
+          }
         file->refcount++;
         eina_lock_release(&file->lock);
      }