* test/mkmf/base.rb (TestMkmf#setup): remove uninitialized global variable.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@35226 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/mkmf/base.rb

@@ -67,7 +67,7 @@ class TestMkmf < Test::Unit::TestCase
     }
     mkconfig = {
       "hdrdir" => "$(top_srcdir)/include",
-      "srcdir" => "$(top_srcdir)/ext/#{$mdir}",
+      "srcdir" => "$(top_srcdir)",
       "topdir" => $topdir,
     }
     rbconfig0.each_pair {|key, val| rbconfig[key] ||= val.dup}