Avoid duplicate symbols produced by emutls

[Jan Hubicka]

Hi,
this patch fixes issue with emutls outputting duplicate ddeifnitions of the vars
it creates becuase it sometimes inserts variable twice (once as alias target and
once as real var).

Bootstrapped/regtested x86_64-linux and HP regtested at at cris-elf.
	PR ipa/61548
	* tree-emutls.c (ipa_lower_emutls): Avoid duplicates in TLS_VARS.
Index: tree-emutls.c
===================================================================
--- tree-emutls.c	(revision 220547)
+++ tree-emutls.c	(working copy)
@@ -753,17 +753,19 @@ ipa_lower_emutls (void)
   cgraph_node *func;
   bool any_aliases = false;
   tree ctor_body = NULL;
-
+  hash_set <varpool_node *> visited;
   auto_vec <varpool_node *> tls_vars;
 
   /* Examine all global variables for TLS variables.  */
   FOR_EACH_VARIABLE (var)
-    if (DECL_THREAD_LOCAL_P (var->decl))
+    if (DECL_THREAD_LOCAL_P (var->decl)
+	&& !visited.add (var))
       {
 	gcc_checking_assert (TREE_STATIC (var->decl)
 			     || DECL_EXTERNAL (var->decl));
 	tls_vars.safe_push (var);
-	if (var->alias && var->definition)
+	if (var->alias && var->definition
+	    && !visited.add (var->ultimate_alias_target ()))
 	  tls_vars.safe_push (var->ultimate_alias_target ());
       }