udhcpc: fix a problem with binary-encoded options

function                                             old     new   delta
attach_option                                        395     413     +18

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c
index 311f79e..0a60261 100644
--- a/networking/udhcp/common.c
+++ b/networking/udhcp/common.c
@@ -375,7 +375,7 @@
 		new->data = xmalloc(length + OPT_DATA);
 		new->data[OPT_CODE] = optflag->code;
 		new->data[OPT_LEN] = length;
-		memcpy(new->data + OPT_DATA, buffer, length);
+		memcpy(new->data + OPT_DATA, (allocated ? allocated : buffer), length);
 
 		curr = opt_list;
 		while (*curr && (*curr)->data[OPT_CODE] < optflag->code)