Index: gcc/config/avr/avr.c
===================================================================
--- gcc/config/avr/avr.c        (revision 183058)
+++ gcc/config/avr/avr.c        (working copy)
@@ -7222,6 +7222,7 @@ avr_encode_section_info (tree decl, rtx
   if (new_decl_p
       && decl && DECL_P (decl)
       && NULL_TREE == DECL_INITIAL (decl)
+      && !DECL_EXTERNAL (decl)
       && avr_progmem_p (decl, DECL_ATTRIBUTES (decl)))
     {
       warning (OPT_Wuninitialized,