[gcn] Set 'UI_NONE' for 'TARGET_EXCEPT_UNWIND_INFO' [PR94282]

In libgomp offloading testing, this resolves all the 'ld: error: undefined
symbol: __gxx_personality_v0' FAILs.

	gcc/
	PR target/94282
	* common/config/gcn/gcn-common.c (gcn_except_unwind_info): New
	function.
	(TARGET_EXCEPT_UNWIND_INFO): Define.
	libgomp/
	PR target/94282
	* testsuite/libgomp.c-c++-common/function-not-offloaded.c: Remove
	'dg-allow-blank-lines-in-output'.

gcc/ChangeLog

+2020-04-29  Thomas Schwinge  <thomas@codesourcery.com>
+
+	PR target/94282
+	* common/config/gcn/gcn-common.c (gcn_except_unwind_info): New
+	function.
+	(TARGET_EXCEPT_UNWIND_INFO): Define.
+
 2020-04-29  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/94248

gcc/common/config/gcn/gcn-common.c

@@ -34,4 +34,13 @@ static const struct default_options gcn_option_optimization_table[] =
 #undef  TARGET_OPTION_OPTIMIZATION_TABLE
 #define TARGET_OPTION_OPTIMIZATION_TABLE gcn_option_optimization_table
 
+static enum unwind_info_type
+gcn_except_unwind_info (struct gcc_options *opts ATTRIBUTE_UNUSED)
+{
+  return UI_NONE;
+}
+
+#undef  TARGET_EXCEPT_UNWIND_INFO
+#define TARGET_EXCEPT_UNWIND_INFO gcn_except_unwind_info
+
 struct gcc_targetm_common targetm_common = TARGETM_COMMON_INITIALIZER;

libgomp/ChangeLog

 2020-04-29  Thomas Schwinge  <thomas@codesourcery.com>
 
+	PR target/94282
+	* testsuite/libgomp.c-c++-common/function-not-offloaded.c: Remove
+	'dg-allow-blank-lines-in-output'.
+
 	* oacc-init.c (get_openacc_name): Handle 'gcn'.
 	* testsuite/lib/libgomp.exp
 	(offload_target_to_openacc_device_type) [amdgcn*]: Return

libgomp/testsuite/libgomp.c-c++-common/function-not-offloaded.c

 /* { dg-do link } */
 /* { dg-excess-errors "unresolved symbol foo, lto1, mkoffload and lto-wrapper fatal errors" { target offload_device_nonshared_as } } */
-/* { dg-allow-blank-lines-in-output 1 } */
 /* { dg-additional-sources "function-not-offloaded-aux.c" } */
 
 #pragma omp declare target