Echange and Enotup should be in error.h to prevent the silly
extern, and redundant static declarations.

Reference: /n/atom/patch/applied/echange
Date: Tue May  6 18:16:05 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/9/port/sdaoe.c	Tue May  6 18:15:40 2014
+++ /sys/src/9/port/sdaoe.c	Tue May  6 18:15:40 2014
@@ -14,9 +14,6 @@
 #include "../port/aoe.h"
 #include <fis.h>
 
-extern	char	Echange[];
-extern	char	Enotup[];
-
 #define uprint(...)	snprint(up->genbuf, sizeof up->genbuf, __VA_ARGS__);
 
 enum {
--- /sys/src/9/port/sdloop.c	Tue May  6 18:15:40 2014
+++ /sys/src/9/port/sdloop.c	Tue May  6 18:15:40 2014
@@ -13,9 +13,6 @@
 #include "../port/sd.h"
 #include "../port/netif.h"
 
-extern	char	Echange[];
-extern	char	Enotup[];
-
 #define uprint(...)	snprint(up->genbuf, sizeof up->genbuf, __VA_ARGS__);
 
 enum {
--- /sys/src/9/port/error.h	Tue May  6 18:15:40 2014
+++ /sys/src/9/port/error.h	Tue May  6 18:15:40 2014
@@ -51,3 +51,5 @@
 extern char Ecmdargs[];		/* wrong #args in control message */
 extern char Ebadip[];		/* bad ip address syntax */
 extern char Edirseek[];		/* seek in directory */
+extern char Echange[];		/* media or partition has changed */
+extern char Enotup[];		/* device is down */
--- /sys/src/9/port/devsd.c	Tue May  6 18:15:40 2014
+++ /sys/src/9/port/devsd.c	Tue May  6 18:15:40 2014
@@ -15,7 +15,6 @@
 extern Dev sddevtab;
 extern SDifc* sdifc[];
 
-static	char	Echange[]	= "media or partition has changed";
 static	char	Enoata[]		= "raw ata commands not supported";
 static	char	Enoscsi[]	= "raw scsi commands not supported";
 
--- /sys/src/9/port/devaoe.c	Tue May  6 18:15:40 2014
+++ /sys/src/9/port/devaoe.c	Tue May  6 18:15:40 2014
@@ -245,8 +245,6 @@
 static	int	debug;
 static	int	autodiscover	= 1;
 static	int	rediscover;
-extern	char 	Enotup[] 	= "aoe device is down";
-extern	char	Echange[]	= "media or partition has changed";
 
 static Srb*
 srballoc(ulong sz)
--- /sys/src/9/port/aoe.h	Tue May  6 18:15:40 2014
+++ /sys/src/9/port/aoe.h	Tue May  6 18:15:40 2014
@@ -119,6 +119,3 @@
 	uchar	nea;
 	uchar	ea0[];
 };
-
-extern char Echange[];
-extern char Enotup[];