Fix "dg-lto-options" misuse

	gcc/testsuite/
	* g++.dg/lto/20080915_0.C: Don't use "dg-lto-options".
	* g++.dg/lto/20080907_0.C: Use "#pragma GCC" instead of
	"dg-lto-options".
	* g++.dg/lto/20101010-1_0.C: Likewise.
	* g++.dg/lto/20101010-2_0.C: Likewise.

Reviewed-by: Jason Merrill <jason@redhat.com>

From-SVN: r258142

gcc/testsuite/ChangeLog

+2018-03-02  Thomas Schwinge  <thomas@codesourcery.com>
+
+	* g++.dg/lto/20080915_0.C: Don't use "dg-lto-options".
+	* g++.dg/lto/20080907_0.C: Use "#pragma GCC" instead of
+	"dg-lto-options".
+	* g++.dg/lto/20101010-1_0.C: Likewise.
+	* g++.dg/lto/20101010-2_0.C: Likewise.
+
 2018-03-02  Jakub Jelinek  <jakub@redhat.com>
 
 	PR ipa/84628

gcc/testsuite/g++.dg/lto/20080907_0.C

 // { dg-lto-do assemble }
-// { dg-lto-options "-Wno-return-type" }
+
+/* "WARNING: lto.exp does not support dg-additional-options" */
+#pragma GCC diagnostic ignored "-Wreturn-type"
 
 struct Foo { void func (); }; Foo & bar () { } struct Baz { Baz (Baz &); };
 Baz dummy() { bar().func(); }

gcc/testsuite/g++.dg/lto/20080915_0.C

 // { dg-lto-do assemble }
-// { dg-lto-options "-Wno-return-type" }
 
 struct Foo {
  static const int dummy;

gcc/testsuite/g++.dg/lto/20101010-1_0.C

 // { dg-lto-do link }
-// { dg-lto-options "-Wno-return-type" }
+
+/* "WARNING: lto.exp does not support dg-additional-options" */
+#pragma GCC diagnostic ignored "-Wreturn-type"
 
 typedef long size_t;
 template < class, class > struct pair

gcc/testsuite/g++.dg/lto/20101010-2_0.C

 // { dg-lto-do link }
-// { dg-lto-options "-Wno-return-type" }
+
+/* "WARNING: lto.exp does not support dg-additional-options" */
+#pragma GCC diagnostic ignored "-Wreturn-type"
 
 typedef int size_t;
 template < size_t _Nw > struct _Base_bitset