adapted ThyLoad.check_file;

--- a/src/Pure/ProofGeneral/pgip_isabelle.ML	Thu Jul 19 23:18:52 2007 +0200
+++ b/src/Pure/ProofGeneral/pgip_isabelle.ML	Thu Jul 19 23:18:54 2007 +0200
@@ -80,7 +80,7 @@
                NONE => (NONE, NONE)
              | SOME fname =>
                let val path = Path.explode fname in
-                 case ThyLoad.check_file NONE path of
+                 case ThyLoad.check_file [] path of
                    SOME _ => (SOME (PgipTypes.pgipurl_of_path path), NONE)
                  | NONE => (NONE, SOME fname)
                end);