Add missing <string.h> includes.

Change-Id: I3d1ad54418f69f947e2d829d63b53d44581bfd86
diff --git a/netcfg/netcfg.c b/netcfg/netcfg.c
index 4e83ba4..204bf1d 100644
--- a/netcfg/netcfg.c
+++ b/netcfg/netcfg.c
@@ -22,6 +22,7 @@
 #include <netutils/ifc.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 void die(const char *reason)
 {