[pushed] Tweak gdb.base/corefile.exp is_remote check

[Pedro Alves <palves at redhat dot com>]

1. Otherwise, when we make native-gdbserver board no longer is_remote,
   we get:

  Running .../src/gdb/testsuite/gdb.base/corefile.exp ...
  ERROR: tcl error sourcing .../src/gdb/testsuite/gdb.base/corefile.exp.
  ERROR: gdbserver does not support attach 9327 without extended-remote
      while executing
  "error "gdbserver does not support $command without extended-remote""

  That's fixed by using can_spawn_for_attach instead.

2. The gdb_protocol check fixes this current problem with
   --target_board=extended-remote-gdbserver:

     Running .../src/gdb/testsuite/gdb.base/corefile.exp ...
     FAIL: gdb.base/corefile.exp: run: with core
     FAIL: gdb.base/corefile.exp: run: core file is cleared
     FAIL: gdb.base/corefile.exp: attach: with core
     FAIL: gdb.base/corefile.exp: attach: core file is cleared

   gdb.log:
     (...)
     attach 10859
     Don't know how to attach.  Try "help target".
     (...)

The fix for #2 alone would fix #1 too, but can_spawn_for_attach
expresses the requirement directly, so I still left it there.

gdb/testsuite/ChangeLog:
2017-10-13  Pedro Alves  <palves@redhat.com>

	* gdb.base/corefile.exp (corefile_test_run): Skip if gdb_protocol
	is set.
	(corefile_test_attach): Likewise.  Check can_spawn_for_attach
	instead of is_remote.
---
 gdb/testsuite/ChangeLog             |  7 +++++++
 gdb/testsuite/gdb.base/corefile.exp | 20 +++++++++++++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 117ab9b..3532ed3 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,5 +1,12 @@
 2017-10-13  Pedro Alves  <palves@redhat.com>
 
+	* gdb.base/corefile.exp (corefile_test_run): Skip if gdb_protocol
+	is set.
+	(corefile_test_attach): Likewise.  Check can_spawn_for_attach
+	instead of is_remote.
+
+2017-10-13  Pedro Alves  <palves@redhat.com>
+
 	* gdb.base/remote.exp: Check gdb_protocol instead of is_remote.
 	(top level): Add comment.
 
diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp
index 21b974f..9be4aef 100644
--- a/gdb/testsuite/gdb.base/corefile.exp
+++ b/gdb/testsuite/gdb.base/corefile.exp
@@ -188,6 +188,15 @@ gdb_test "core" "No core file now."
 proc corefile_test_run {} {
     global corefile gdb_prompt
 
+    # This test is trying to check whether the "run" command finds the
+    # default run target when already debugging a core, so it would
+    # fail on boards that set auto-connect-native-target off.  Since
+    # there's no real point in running the test but with the native
+    # target, it's easier to just skip elsewhere.
+    if {[target_info gdb_protocol] != ""} {
+	return
+    }
+
     gdb_test "core-file $corefile" "Core was generated by .*" "run: load core again"
     gdb_test "info files" "\r\nLocal core dump file:\r\n.*" "run: sanity check we see the core file"
 
@@ -244,7 +253,16 @@ gdb_exit
 proc corefile_test_attach {} {
     global binfile corefile gdb_prompt
 
-    if ![is_remote target] {
+    # This test is checking whether the "attach" command finds the
+    # default run target when already debugging a core, so it would
+    # fail on boards that set auto-connect-native-target off.  Since
+    # there's no real point in running the test but with the native
+    # target, it's easier to just skip elsewhere.
+    if {[target_info gdb_protocol] != ""} {
+	return
+    }
+
+    if [can_spawn_for_attach] {
 	set test "attach: spawn sleep"
 	set res [remote_spawn host "$binfile sleep"]
 	if { $res < 0 || $res == "" } {
-- 
2.5.5