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

diff --git a/coreutils/chown.c b/coreutils/chown.c
index d974493..df3b77d 100644
--- a/coreutils/chown.c
+++ b/coreutils/chown.c
@@ -61,7 +61,7 @@
 	return FALSE;
 }
 
-int chown_main(int argc, char **argv);
+int chown_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int chown_main(int argc, char **argv)
 {
 	int retval = EXIT_SUCCESS;