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

diff --git a/networking/nameif.c b/networking/nameif.c
index 2114516..0369c08 100644
--- a/networking/nameif.c
+++ b/networking/nameif.c
@@ -55,7 +55,7 @@
 	return mac;
 }
 
-int nameif_main(int argc, char **argv);
+int nameif_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int nameif_main(int argc, char **argv)
 {
 	mactable_t *clist = NULL;