bug#18237: Small fix for MSDOS

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 10 Aug 2014 17:40:24 +0100
> From: Reuben Thomas <rrt@sc3d.org>
> 
> The following patch helps in the case when a sockets library is installed;
> in my case, ls080b.zip from the DJGPP site:
> 
> === modified file 'src/msdos.c'
> --- src/msdos.c    2014-08-09 16:12:33 +0000
> +++ src/msdos.c    2014-08-09 21:51:56 +0000
> @@ -4016,7 +4017,7 @@
>  #endif
> 
> 
> -#ifndef HAVE_SELECT
> +#ifndef HAVE_SYS_SELECT_H
>  #include "sysselect.h"
> 
>  /* This yields the rest of the current time slice to the task manager.
> 
> 
> The reasoning is that having select doesn't imply having the sys/select.h
> functionality that the following code emulates.
> 
> Does that look OK to install?

You didn't tell enough details, so I don't understand why the change
is needed, and why it is OK not to test HAVE_SELECT at all here.  (I
don't have ls080b.zip installed.)  Please tell what problems did you
see with the original code, and let's take it from there.

Thanks.