r23528: Two changes to make the valgrind massif (heap profiler) output readable:

Remove the allocated inbuf/output. In async I/O we copy the buffers
explicitly now, so NewInBuffer is called exactly once. This does not
reduce memory footprint, but removes one of the larger chunks that
clobber the rest of the massif output

In getgroups_unix_user on Linux 2.6 we allocated 64k groups x 4 bytes
per group x 2 (once in the routine itself and once in libc) = 512k just
to throw it away directly again. This reduces it do a more typical limit
of 32 groups per user. We certainly cope with overflow fine if 32 is not
enough. Not 100% sure about this one, a DEVELOPER only thing?

source/lib/system_smbd.c

@@ -154,7 +154,7 @@ BOOL getgroups_unix_user(TALLOC_CTX *mem_ctx, const char *user,
 	gid_t *groups;
 	int i;
 
-	max_grp = groups_max();
+	max_grp = MIN(32, groups_max());
 	temp_groups = SMB_MALLOC_ARRAY(gid_t, max_grp);
 	if (! temp_groups) {
 		return False;