suppress warnings about easch <applet>_main() having

no preceding prototype

init/halt.c

@@ -10,6 +10,7 @@
 #include "busybox.h"
 #include <sys/reboot.h>
 
+int halt_main(int argc, char *argv[]);
 int halt_main(int argc, char *argv[])
 {
 	static const int magic[] = {

init/init.c

@@ -968,6 +968,7 @@ static void reload_signal(int sig ATTRIBUTE_UNUSED)
 }
 #endif  /* FEATURE_USE_INITTAB */
 
+int init_main(int argc, char **argv);
 int init_main(int argc, char **argv)
 {
 	struct init_action *a;

init/mesg.c

@@ -15,6 +15,7 @@
 #define S_IWGRP_OR_S_IWOTH	(S_IWGRP | S_IWOTH)
 #endif
 
+int mesg_main(int argc, char *argv[]);
 int mesg_main(int argc, char *argv[])
 {
 	struct stat sb;