Add some missing errnos from POSIX. Nothing in FreeBSD generates

these at the moment, but applications that test for them will now
have a better chance of compiling.

I have intentionally omitted errnos that are only good for STREAMS,
since apps that use STREAMS won't compile anyway.  The exception is
EPROTO, which was apparently intended for STREAMS, but worth having
anyway because Linux (mis)uses it for other things.

lib/libc/gen/errlst.c

@@ -149,5 +149,10 @@ const char *const sys_errlist[] = {
 
 /* General */
 	"Programming error",			/* 88 - EDOOFUS */
+
+	"Bad message",				/* 89 - EBADMSG */
+	"Multihop attempted",			/* 90 - EMULTIHOP */
+	"Link has been severed",		/* 91 - ENOLINK */
+	"Protocol error",			/* 92 - EPROTO */
 };
 const int sys_nerr = sizeof(sys_errlist) / sizeof(sys_errlist[0]);

sys/sys/errno.h

@@ -166,9 +166,15 @@ __END_DECLS
 #define	ENOATTR		87		/* Attribute not found */
 
 #define EDOOFUS		88		/* Programming error */
+#endif /* _POSIX_SOURCE */
 
-#define	ELAST		88		/* Must be equal largest errno */
+#define	EBADMSG		89		/* Bad message */
+#define	EMULTIHOP	90		/* Multihop attempted */
+#define	ENOLINK		91		/* Link has been severed */
+#define	EPROTO		92		/* Protocol error */
 
+#ifndef _POSIX_SOURCE
+#define	ELAST		92		/* Must be equal largest errno */
 #endif /* _POSIX_SOURCE */
 
 #ifdef _KERNEL