Bug fix: Prolog version of builtin_aggregate

[Thomas Charles CONWAY]

Hi

The following diff adds a definition of builtin_aggregate for
Prolog.

-- 
ZZ:wq!
^X^C
Thomas Conway               				      conway at cs.mu.oz.au
AD DEUM ET VINUM	  			      Every sword has two edges.

library/std_util.m:
	Add a definition of builtin_aggregate for Prolog.

cvs diff: Diffing .
Index: std_util.nu.nl
===================================================================
RCS file: /home/staff/zs/imp/mercury/library/std_util.nu.nl,v
retrieving revision 1.15
diff -u -r1.15 std_util.nu.nl
--- std_util.nu.nl	1997/07/27 15:07:18	1.15
+++ std_util.nu.nl	1997/10/06 02:45:31
@@ -76,6 +76,12 @@
 
 %-----------------------------------------------------------------------------%
 
+builtin_aggregate(P, A, Acc0, Acc) :-
+	findall(X, call(P, X), L),
+	list__foldl(A, L, Acc0, Acc).
+
+%-----------------------------------------------------------------------------%
+
 % This is buggy in the backwards mode, but it will just have to do for
 % the moment.