fix errno usage in scheduler/sysdeps.c on NetBSD

[Yorick Hardy]

The patch below works around the fact that NetBSD uses a macro to define
errno, thus errno should not be used as a variable name.

-- 
Yorick Hardy

--- scheduler/sysdeps.c	Thu Apr  3 20:56:13 2003
+++ scheduler/sysdeps.c	Sat Apr 12 12:50:14 2003
@@ -362,8 +362,8 @@
 /* default errno before threading is initialized */
 static int *default_errno_location(void)
 {
-    static int errno;
-    return &errno;
+    static int serrno;
+    return &serrno;
 }
 
 /* default h_errno before threading is initialized */