Robert P. Day removed 8 gazillion occurrences of "extern" on function
definitions.  (That should only be on prototypes.)
diff --git a/libbb/perror_msg.c b/libbb/perror_msg.c
index 8ba0531..a0fdabc 100644
--- a/libbb/perror_msg.c
+++ b/libbb/perror_msg.c
@@ -25,7 +25,7 @@
 #include <stdlib.h>
 #include "libbb.h"
 
-extern void bb_perror_msg(const char *s, ...)
+void bb_perror_msg(const char *s, ...)
 {
 	va_list p;