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

diff --git a/editors/ed.c b/editors/ed.c
index 31185d9..cceff0c 100644
--- a/editors/ed.c
+++ b/editors/ed.c
@@ -88,7 +88,7 @@
 }
 
 
-int ed_main(int argc, char **argv);
+int ed_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int ed_main(int argc, char **argv)
 {
 	INIT_G();