allow 64-bit operations with OLIST (,) operator.

Reference: /n/sources/patch/applied/cc64inlist
Date: Sun Dec  5 14:26:49 CET 2010
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/cc/com64.c	Sun Dec  5 14:24:15 2010
+++ /sys/src/cmd/cc/com64.c	Sun Dec  5 14:24:14 2010
@@ -274,6 +274,7 @@
 		case ORETURN:
 		case OAS:
 		case OIND:
+		case OLIST:
 			return 1;
 		case OADD:
 			a = nodaddv;