add -fvisibility=hidden to CC flags, mark XXX_main functions
EXTERNALLY_VISIBLE. 5% size reduction of libbusybox.so

diff --git a/networking/udhcp/dumpleases.c b/networking/udhcp/dumpleases.c
index 3e931c0..218e6bc 100644
--- a/networking/udhcp/dumpleases.c
+++ b/networking/udhcp/dumpleases.c
@@ -7,7 +7,7 @@
 #include "common.h"
 #include "dhcpd.h"
 
-int dumpleases_main(int argc, char **argv);
+int dumpleases_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int dumpleases_main(int argc, char **argv)
 {
 	int fd;