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

diff --git a/util-linux/freeramdisk.c b/util-linux/freeramdisk.c
index 4bd9378..bde6afc 100644
--- a/util-linux/freeramdisk.c
+++ b/util-linux/freeramdisk.c
@@ -14,7 +14,7 @@
 /* From <linux/fd.h> */
 #define FDFLUSH  _IO(2,0x4b)
 
-int freeramdisk_main(int argc, char **argv);
+int freeramdisk_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int freeramdisk_main(int argc, char **argv)
 {
 	int fd;