mail/serialmail: include errno.h for errno

errno must be accessed by a macro from errno.h.

mail/serialmail/Makefile

 PORTNAME=	serialmail
 PORTVERSION=	0.75
-PORTREVISION=	4
+PORTREVISION=	5
 CATEGORIES=	mail
 MASTER_SITES=	http://cr.yp.to/software/ \
 		ftp://ftp.gbnet.net/pub/qmail/ \

mail/serialmail/files/patch-error.h

+--- error.h.orig
++++ error.h
+@@ -1,7 +1,7 @@
+ #ifndef ERROR_H
+ #define ERROR_H
+ 
+-extern int errno;
++#include <errno.h>
+ 
+ extern int error_intr;
+ extern int error_nomem;

mail/serialmail/files/patch-leapsecs__read.c

+--- leapsecs_read.c.orig
++++ leapsecs_read.c
+@@ -2,7 +2,6 @@
+ #include <sys/stat.h>
+ #include <fcntl.h>
+ #include <errno.h>
+-extern int errno;
+ #include "tai.h"
+ #include "leapsecs.h"
+