Robert P. Day removed 8 gazillion occurrences of "extern" on function
definitions.  (That should only be on prototypes.)
diff --git a/coreutils/logname.c b/coreutils/logname.c
index e2a74f9..da8a1cf 100644
--- a/coreutils/logname.c
+++ b/coreutils/logname.c
@@ -25,7 +25,7 @@
 #include <unistd.h>
 #include "busybox.h"
 
-extern int logname_main(int argc, char ATTRIBUTE_UNUSED **argv)
+int logname_main(int argc, char ATTRIBUTE_UNUSED **argv)
 {
 	const char *p;