lib: add uuid_str_to_bin for use with bootp and PXE uuid

Signed-off-by: Jason Hobbs <jason.hobbs@calxeda.com>
diff --git a/lib/Makefile b/lib/Makefile
index 884f64c..075bb8c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -55,6 +55,7 @@
 COBJS-y += div64.o
 COBJS-y += string.o
 COBJS-y += time.o
+COBJS-$(CONFIG_BOOTP_PXE) += uuid.o
 COBJS-y += vsprintf.o
 
 COBJS	:= $(COBJS-y)