also consider current working directory (cf. 3a5a5a992519)

--- a/src/Tools/Code/code_target.ML	Sat Jul 21 17:49:22 2012 +0200
+++ b/src/Tools/Code/code_target.ML	Sat Jul 21 20:01:16 2012 +0200
@@ -373,7 +373,8 @@
 fun assert_module_name "" = error ("Empty module name not allowed.")
   | assert_module_name module_name = module_name;
 
-fun using_master_directory thy = Option.map (Path.append (Thy_Load.master_directory thy));
+fun using_master_directory thy =
+  Option.map (Path.append (File.pwd ()) o Path.append (Thy_Load.master_directory thy));
 
 in