Pass $(XRUBY) to test-bundled-gems.rb since RbConfig.ruby is incorrect for miniruby

template/Makefile.in

@@ -536,7 +536,7 @@ cont.$(OBJEXT): $(COROUTINE_H)
 TEST_BUNDLED_GEMS_ALLOW_FAILURES =
 
 test-bundled-gems-run:
-	$(Q) $(XRUBY) $(srcdir)/tool/test-bundled-gems.rb
+	$(Q) $(XRUBY) $(srcdir)/tool/test-bundled-gems.rb $(XRUBY)
 
 update-src::
 	@$(CHDIR) "$(srcdir)" && LC_TIME=C exec $(VCSUP)

tool/test-bundled-gems.rb

@@ -9,7 +9,7 @@ File.foreach('gems/bundled_gems') do |line|
   puts "\nTesting the #{gem} gem"
 
   gem_src_dir = File.expand_path("../../gems/src/#{gem}", __FILE__ )
-  test_command = "#{RbConfig.ruby} -C #{gem_src_dir} -Ilib ../../../.bundle/bin/rake"
+  test_command = "#{ARGV.join(' ')} -C #{gem_src_dir} -Ilib ../../../.bundle/bin/rake"
   puts test_command
   system test_command