fixed error msgs;

--- a/src/Pure/theory.ML	Wed May 27 12:25:56 1998 +0200
+++ b/src/Pure/theory.ML	Thu May 28 11:08:45 1998 +0200
@@ -355,7 +355,7 @@
 (* check_defn *)
 
 fun err_in_defn sg name msg =
-  (writeln msg; error ("The error(s) above occurred in definition " ^
+  (error_msg msg; error ("The error(s) above occurred in definition " ^
     quote (Sign.full_name sg name)));
 
 fun check_defn sign (axms, (name, tm)) =

--- a/src/Pure/type.ML	Wed May 27 12:25:56 1998 +0200
+++ b/src/Pure/type.ML	Thu May 28 11:08:45 1998 +0200
@@ -573,7 +573,7 @@
 
 fun prep_abbr tsig (a, vs, raw_rhs) =
   let
-    fun err msgs = (seq writeln msgs;
+    fun err msgs = (seq error_msg msgs;
       error ("The error(s) above occurred in type abbreviation " ^ quote a));
 
     val rhs = rem_sorts (varifyT (no_tvars raw_rhs))