MFC of r199642

The output of perror(1) is now showing local messages for locales
supported by libc/nls

PR:             bin/140499
Approved by:    gnn@

usr.bin/perror/perror.c

@@ -32,6 +32,7 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 #include <string.h>
 #include <err.h>
+#include <locale.h>
 #include <sys/errno.h>
 
 static void usage(void);
@@ -43,6 +44,7 @@ main(int argc, char **argv)
 	char *errstr;
 	long errnum;
 
+	(void) setlocale(LC_MESSAGES, "");
 	if (argc != 2)
 		usage();