S/390: Initialize variable to avoid warning

gcc/ChangeLog:

2017-04-05  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* config/s390/s390-c.c (s390_resolve_overloaded_builtin):
	Initialize last_match_fntype_index.

From-SVN: r246700

gcc/ChangeLog

+2017-04-05  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
+
+	* config/s390/s390-c.c (s390_resolve_overloaded_builtin):
+	Initialize last_match_fntype_index.
+
 2017-04-05  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/80310

gcc/config/s390/s390-c.c

@@ -854,7 +854,7 @@ s390_resolve_overloaded_builtin (location_t loc,
   const unsigned int ob_flags = bflags_for_builtin(ob_fcode);
   int num_matches = 0;
   tree target_builtin_decl, b_arg_chain, return_type;
-  enum s390_builtin_ov_type_index last_match_fntype_index;
+  enum s390_builtin_ov_type_index last_match_fntype_index = BT_OV_MAX;
 
   if (TARGET_DEBUG_ARG)
     fprintf (stderr,