fix a problem that chainloader doesn't report any error, even if it failed.

ChangeLog

@@ -1,3 +1,9 @@
+2000-12-17  OKUJI Yoshinori  <okuji@gnu.org>
+
+	* stage2/builtins.c (chainloader_func): Set ERRNUM to
+	ERR_EXEC_FORMAT, when ERRNUM is ERR_NONE, even if grub_read
+	fails in reading one sector.
+	
 2000-12-14  OKUJI Yoshinori  <okuji@gnu.org>
 
 	* docs/prog-ref.texi (Partition types): Rewrite the footnotes.

stage2/builtins.c

@@ -418,6 +418,12 @@ chainloader_func (char *arg, int flags)
     {
       grub_close ();
       kernel_type = KERNEL_TYPE_NONE;
+
+      /* This below happens, if a file whose size is less than 512 bytes
+	 is loaded.  */
+      if (errnum == ERR_NONE)
+	errnum = ERR_EXEC_FORMAT;
+      
       return 1;
     }