diff -up pax-3.4/src/extern.h.me pax-3.4/src/extern.h
--- pax-3.4/src/extern.h.me	2020-01-31 13:41:27.520585130 +0100
+++ pax-3.4/src/extern.h	2020-01-31 13:41:46.366376773 +0100
@@ -185,7 +185,7 @@ void options(int, char **);
 OPLIST * opt_next(void);
 int opt_add(const char *);
 int bad_opt(void);
-char *chdname;
+extern char *chdname;
 
 /*
  * pat_rep.c
diff -up pax-3.4/src/options.c.me pax-3.4/src/options.c
--- pax-3.4/src/options.c.me	2020-01-31 13:43:45.988955243 +0100
+++ pax-3.4/src/options.c	2020-01-31 14:25:13.558764306 +0100
@@ -83,6 +83,8 @@ static int my_getline_error;
 #define GZIP_CMD	"gzip"	/* command to run as gzip */
 #define COMPRESS_CMD	"compress"	/* command to run as compress */
 
+char *chdname;
+
 /*
  *	Format specific routine table - MUST BE IN SORTED ORDER BY NAME
  *	(see pax.h for description of each function)
@@ -724,6 +726,7 @@ tar_options (int argc, char **argv)
 	case 'o':
 	  if (opt_add ("write_opt=nodir") < 0)
 	    tar_usage ();
+	  /* FALLTHROUGH */
 	case 'O':
 	  Oflag = 1;
 	  break;