Fixed merging error. Lite2 fixed premature failure and didn't

touch duplicate group suppression, but the merge blew away our
duplicate group suppression.

The merge also blew away the -Wall cleanup in rev.1.5, but that
was misformatted, so I didn't restore it.

lib/libc/gen/getgrouplist.c

@@ -69,8 +69,10 @@ getgrouplist(uname, agroup, groups, grpcnt)
 	 */
 	setgrent();
 	while (grp = getgrent()) {
-		if (grp->gr_gid == agroup)
-			continue;
+		for (i = 0; i < ngroups; i++) {
+			if (grp->gr_gid == groups[i])
+				goto skip;
+		}
 		for (i = 0; grp->gr_mem[i]; i++) {
 			if (!strcmp(grp->gr_mem[i], uname)) {
 				if (ngroups >= maxgroups) {