Robert P. Day removed 8 gazillion occurrences of "extern" on function
definitions.  (That should only be on prototypes.)
diff --git a/coreutils/who.c b/coreutils/who.c
index e2ea227..1156ba2 100644
--- a/coreutils/who.c
+++ b/coreutils/who.c
@@ -25,7 +25,7 @@
 #include <time.h>
 #include "busybox.h"
 
-extern int who_main(int argc, char **argv)
+int who_main(int argc, char **argv)
 {
     struct utmp *ut;
     struct stat st;