Make errno finally and permanently thread-aware so that it is no longer

necessary to compile with _THREAD_SAFE defined. This means that people
will get thread-aware code whether they like it or not. This change
is required to allow a process to link against libpthread and libc
to use kernel threads (and prevent each thread from clobbering another
thread's errno just be doing a syscall).

This is bound to break some ports, but it is strictly allowed by ANSI C,
so anything that breaks as a result was already broken anyway 8-).
"Sorry".

sys/sys/errno.h

@@ -36,22 +36,18 @@
  * SUCH DAMAGE.
  *
  *	@(#)errno.h	8.5 (Berkeley) 1/21/94
- * $Id: errno.h,v 1.8 1997/12/06 11:28:06 bde Exp $
+ * $Id: errno.h,v 1.9 1998/04/13 17:45:00 sos Exp $
  */
 
 #ifndef _SYS_ERRNO_H_
 #define _SYS_ERRNO_H_
 
 #ifndef KERNEL
-#ifdef	_THREAD_SAFE
 #include <sys/cdefs.h>
 __BEGIN_DECLS
 int *	__error __P((void));
 __END_DECLS
 #define	errno		(* __error())
-#else
-extern int errno;			/* global error number */
-#endif
 #endif
 
 #define	EPERM		1		/* Operation not permitted */