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

diff --git a/coreutils/mkfifo.c b/coreutils/mkfifo.c
index e66f817..d298ada 100644
--- a/coreutils/mkfifo.c
+++ b/coreutils/mkfifo.c
@@ -13,7 +13,7 @@
 #include "libbb.h"
 #include "libcoreutils/coreutils.h"
 
-int mkfifo_main(int argc, char **argv);
+int mkfifo_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int mkfifo_main(int argc, char **argv)
 {
 	mode_t mode;