[gdb/testsuite] Make is_64_target more robust

I ran test-case gdb.dwarf2/opt-out-not-implptr.exp with make-check-all.sh, and
with target board dwarf64 ran into:
...
FAIL: gdb.dwarf2/opt-out-not-implptr.exp: print noptr
...
due to is_target_64 failing because of:
...
builtin_spawn -ignore SIGHUP gcc -fno-stack-protector \
  -fdiagnostics-color=never -w -c -gdwarf64 -g -o is_64_target.o \
  is_64_target.c^M
gcc: error: '-gdwarf64' is ambiguous; use '-gdwarf-64' for DWARF version or \
  '-gdwarf -g64' for debug level^M
compiler exited with status 1
...

The FAIL is the same FAIL I run into with target board unix/-m32: is_target_64
fails for both cases.

The reason that is_target_64 is failing for target board dwarf64, is because
of using system compiler 7.5.0 which doesn't support -gdwarf64.

Fix this by making is_target_64 use nodebug instead of debug for compilation.

Tested on x86_64-linux.

1 files changed, 8 insertions, 1 deletions

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 50c10333df1..010da097766 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -3492,7 +3492,7 @@ gdb_caching_proc is_lp64_target {} {
 # This cannot be decided simply from looking at the target string,
 # as it might depend on externally passed compiler options like -m64.
 gdb_caching_proc is_64_target {} {
-    return [gdb_can_simple_compile is_64_target {
+    return [gdb_can_simple_compile_nodebug is_64_target {
 	int function(void) { return 3; }
 	int dummy[sizeof (&function) == 8 ? 1 : -1];
     }]
@@ -4736,6 +4736,13 @@ proc gdb_can_simple_compile {name code {type object} {compile_flags ""} {default
     return $ret
 }
 
+# As gdb_can_simple_compile, but defaults to using nodebug instead of debug.
+proc gdb_can_simple_compile_nodebug {name code {type object} {compile_flags ""}
+				     {default_compile_flags "nodebug nowarning quiet"}} {
+    return [gdb_can_simple_compile $name $code $type $compile_flags \
+		$default_compile_flags]
+}
+
 # Some targets need to always link a special object in.  Save its path here.
 global gdb_saved_set_unbuffered_mode_obj
 set gdb_saved_set_unbuffered_mode_obj ""