Subject: [bug#34982] [PATCH] guile-build-system: Support building in parallel.

From: Ludovic Courtès <[email-masked]>
Date: Tue, 16 Apr 2019 21:30:21 +0200

Christopher Baines <[email-masked]> skribis:

> * guix/build/guile-build-system.scm (build): Use invoke-each, instead of
> for-each, to use multiple cores if available.
> (invoke-each, report-build-process): New procedures.

[...]

> +  (define (fork-and-run-command command)
> +    (match (primitive-fork)
> +      (0
> +       (apply execlp command))
> +      (pid
> +       #t)))

To be on the safe side, you should probably wrap the ‘execlp’ call like
this:

  (dynamic-wind
    (const #t)
    (lambda ()
      (apply execlp command))
    (lambda ()
      (primitive-exit 127)))

This ensures that the child process exits immediately if something goes
wrong (e.g., ‘execlp’ raises an exception because the executable could
not be found.)

Otherwise LGTM, thank you!

Ludo’.