changed mechanism for for-loop checking, added some trap numbers

lang/m2/libm2/LIST

@@ -16,7 +16,6 @@ Semaphores.mod
 random.mod
 Strings.mod
 catch.c
-FORchk.c
 Traps.mod
 Arguments.c
 LtoUset.e

lang/m2/libm2/Makefile

@@ -11,4 +11,4 @@ all:
 
 install:
 		-mkdir $(DEFDIR)
-		for i in $(SOURCES) ; do cp $$i $(DEFDIR)/$$i ; done
+		cp $(SOURCES) $(DEFDIR)

lang/m2/libm2/Traps.def

@@ -7,6 +7,9 @@ DEFINITION MODULE Traps;
 	ERRTOOMANY =	65;	(* too many nested traps + handlers *)
 	ERRNORESULT =	66;	(* no RETURN from function procedure *)
 	ERRCARDOVFL =	67;	(* CARDINAL overflow *)
+	ERRFORLOOP =	68;	(* value of FOR-loop control variable changed
+				   in loop
+				*)
 
   TYPE	TrapHandler = EM.TrapHandler;
 

lang/m2/libm2/catch.c

@@ -34,6 +34,7 @@ static struct errm {
 	{ M2_TOOMANY,	"too many nested traps + handlers"},
 	{ M2_NORESULT,	"no RETURN from procedure function"},
 	{ M2_UOVFL,	"cardinal overflow"},
+	{ M2_FORCH,	"Warning: FOR-loop control variable was changed in the body"},
 	{ -1,		0}
 };
 
@@ -70,5 +71,6 @@ _catch(trapno)
 		*p = 0;
 		Traps_Message(q, 0, (int) (p - q), 1);
 	}
-	exit(trapno);
+	if (trapno != M2_FORCH) exit(trapno);
+	SIG(_catch);
 }