Re: guile 2.0.9 build on mingw

[Eli Zaretskii <eliz@gnu.org>]

> From: ludo@gnu.org (Ludovic Courtès)
> Cc: mhw@netris.org,  guile-user@gnu.org
> Date: Sun, 16 Jun 2013 16:36:50 +0200
> 
> > The patch below, which should be applied on top of the one I sent
> > yesterday, is needed because open-pipe does this:
> >
> >      (open-pipe* mode "/bin/sh" "-c" command))
> >
> > and obviously there's no /bin/sh on Windows.
> >
> > --- libguile/posix.c~1	2013-06-13 08:54:44.926293300 +0300
> > +++ libguile/posix.c	2013-06-13 08:57:44.262743700 +0300
> > @@ -1300,7 +1300,9 @@ scm_open_process (SCM mode, SCM prog, SC
> >    int pid;
> >    char *exec_file;
> >    char **exec_argv;
> > +#ifdef HAVE_FORK
> >    int max_fd = 1024;
> > +#endif
> 
> The #ifdef appears unnecessary given that this is already in #ifdef HAVE_FORK.

As I wrote above, this was supposed to be applied on top of what I
sent here:

  http://lists.gnu.org/archive/html/guile-user/2013-06/msg00033.html

which, among other things, inserted "#endif" before scm_open_process,
thus making it available when fork isn't.

> This last hunk doesn’t apply since the whole thing is already in
> #ifdef HAVE_FORK AFAICS.

See above.  The intent was to make open-process available on Windows,
so ifdef'ing all of it conditioned on fork would be
counter-productive...

> What about this (hopefully simpler) patch instead?
> 
> diff --git a/module/ice-9/popen.scm b/module/ice-9/popen.scm
> index 7d0549e..e431949 100644
> --- a/module/ice-9/popen.scm
> +++ b/module/ice-9/popen.scm
> @@ -61,13 +61,23 @@ port to the process is created: it should be the value of
>          (hashq-set! port/pid-table port pid)
>          port))))
>  
> +(define %shell-command
> +  (cond ((file-exists? "/bin/sh")
> +         "/bin/sh")
> +        ((getenv "SHELL")
> +         ;; Hope that $SHELL points at a Bourne-compatible shell.
> +         => identity)
> +        (else
> +         ;; Assume we're on Windows.
> +         "cmd.exe")))
> +
>  (define (open-pipe command mode)
>    "Executes the shell command @var{command} (a string) in a subprocess.
>  A port to the process (based on pipes) is created and returned.
>  @var{mode} specifies whether an input, an output or an input-output
>  port to the process is created: it should be the value of
>  @code{OPEN_READ}, @code{OPEN_WRITE} or @code{OPEN_BOTH}."
> -  (open-pipe* mode "/bin/sh" "-c" command))
> +  (open-pipe* mode %shell-command "-c" command))
>  
>  (define (fetch-pid port)
>    (let ((pid (hashq-ref port/pid-table port)))

The "-c" part needs to be replaced with "/c".  And that would only
take care of open-pipe; there are more instances of using /bin/sh
etc. elsewhere in Guile.  If we want to handle this on the Scheme
level, it will be necessary to consistently discourage people from
using explicit shell file names and instead use %shell-file-name and
%shell-command-switch, like Emacs does.

And the parts of scm_open_process that replace the Unix fork/exec
stuff will still be needed, just without rewriting exec_file and
exec_arg[].

Thanks.