diff --git a/tool/mkconfig.rb b/tool/mkconfig.rb
index 243ffa12c4..a2221f0032 100755
--- a/tool/mkconfig.rb
+++ b/tool/mkconfig.rb
@@ -152,7 +152,7 @@ print <<'ARCH' if universal
   arch_flag = ENV['ARCHFLAGS'] || ((e = ENV['RC_ARCHS']) && e.split.uniq.map {|a| "-arch #{a}"}.join(' '))
   arch = arch_flag && arch_flag[/\A\s*-arch\s+(\S+)\s*\z/, 1]
 ARCH
-print "  universal = #{universal}\n"
+print "  universal = #{universal}\n" if universal
 print "  CONFIG = {}\n"
 print "  CONFIG[\"DESTDIR\"] = DESTDIR\n"