Call _cleanup before _exit

lang/m2/libm2/SYSTEM.c

@@ -71,6 +71,7 @@ _SYSTEM__NEWPROCESS(p, a, n, p1)
 		   Just call the coroutine procedure.
 		*/
 		(*(curproc->proc))();
+		_cleanup();
 		_exit(0);
 	}
 }

lang/m2/libm2/catch.c

@@ -52,8 +52,6 @@ static struct errm {
 	{ -1,		0}
 };
 
-extern			exit();
-
 catch(trapno)
 	int trapno;
 {
@@ -93,11 +91,14 @@ catch(trapno)
 		signal(__signo, SIG_DFL);
 		_cleanup();
 		kill(getpid(), __signo);
-		exit(trapno);
+		_exit(trapno);
 	}
 #endif
 #endif
 #endif
-	if (trapno != M2_FORCH) exit(trapno);
+	if (trapno != M2_FORCH) {
+		_cleanup();
+		_exit(trapno);
+	}
 	SIG(catch);
 }

lang/m2/libm2/halt.c

@@ -32,5 +32,6 @@ CallAtEnd(p)
 
 halt()
 {
-	exit(0);
+	_cleanup();
+	_exit(0);
 }