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

diff --git a/runit/svlogd.c b/runit/svlogd.c
index bf46ef7..5f682b1 100644
--- a/runit/svlogd.c
+++ b/runit/svlogd.c
@@ -843,7 +843,7 @@
 	}
 }
 
-int svlogd_main(int argc, char **argv);
+int svlogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int svlogd_main(int argc, char **argv)
 {
 	char *r,*l,*b;