[binutils-gdb] Don't let .gdb_history file cause failures

[Tom Tromey <tromey@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=300fa060abbfd8d36c81d8cc777ea1f32f07b4f0

commit 300fa060abbfd8d36c81d8cc777ea1f32f07b4f0
Author: Tom Tromey <tromey@adacore.com>
Date:   Thu Jan 19 11:19:32 2023 -0700

    Don't let .gdb_history file cause failures
    
    I had a .gdb_history file in my testsuite directory in the build tree,
    and this provoked a failure in gdbhistsize-history.exp.  It seems
    simple to prevent this file from causing a failure.

Diff:
---
 gdb/testsuite/gdb.base/gdbhistsize-history.exp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gdb/testsuite/gdb.base/gdbhistsize-history.exp b/gdb/testsuite/gdb.base/gdbhistsize-history.exp
index 59fd2d0c143..00c3ea4dde2 100644
--- a/gdb/testsuite/gdb.base/gdbhistsize-history.exp
+++ b/gdb/testsuite/gdb.base/gdbhistsize-history.exp
@@ -35,6 +35,10 @@ proc test_histsize_history_setting { histsize size { env_var "GDBHISTSIZE" } } {
 	unset -nocomplain env(GDBHISTFILE)
 	unset -nocomplain env(GDBHISTSIZE)
 
+	# Ensure we don't accidentally pick up a .gdb_history from the
+	# testsuite directory.
+	set env(GDBHISTFILE) [standard_output_file .gdb_history]
+
 	set env($env_var) $histsize
 
 	with_test_prefix "histsize=$histsize" {