From c2a08ef876e3a8caa95d29eb9683ec63d77ebf1c Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 7 Nov 2017 11:21:09 +0000
Subject: [PATCH] tool/runruby.rb: fix RUNRUBY_USE_GDB case

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60698 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 tool/runruby.rb | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tool/runruby.rb b/tool/runruby.rb
index 662c0aef35..a5aa3e7d8d 100755
--- a/tool/runruby.rb
+++ b/tool/runruby.rb
@@ -131,7 +131,7 @@ end
 ENV.update env
 
 if debugger or ENV['RUNRUBY_USE_GDB'] == 'true'
-  if debugger == :gdb
+  if debugger == :gdb or !debugger
     debugger = %w'gdb'
     if File.exist?(gdb = 'run.gdb') or
       File.exist?(gdb = File.join(abs_archdir, 'run.gdb'))
@@ -139,7 +139,11 @@ if debugger or ENV['RUNRUBY_USE_GDB'] == 'true'
     end
     debugger << '--args'
   end
-  precommand[precommand.index(:debugger), 1] = debugger
+  if idx = precommand.index(:debugger)
+    precommand[idx, 1] = debugger
+  else
+    precommand.concat(debugger)
+  end
 end
 
 cmd = [runner || ruby]