Re: [PATCH 1/4] gnu: base: Add glibc-hurd and hurd-minimal.

[Mark H Weaver]

Mark H Weaver <address@hidden> writes:

> Manolis Ragkousis <address@hidden> writes:
>
>> +       ,@(substitute-keyword-arguments (package-arguments glibc)
>> +           ((#:configure-flags cf)
>> +            `(append (list "--host=i686-pc-gnu"
>> +
>> +                           ;; nscd fails to build for GNU/Hurd:
>> +                           ;; 
>> <https://lists.gnu.org/archive/html/bug-hurd/2014-07/msg00006.html>.
>> +                           ;; Disable it.
>> +                           "--disable-nscd")))
>
> Did you intend to omit 'cf', the inherited configure-flags from 'glibc'?
> Also, you're passing only one argument to 'append', making it a no-op.
>
> Looking at the configure-flags for 'glibc', most of them look desirable
> on Hurd, but some of them don't.  [...]
[...]
> How about this: (untested)
>
>            ((#:configure-flags original-configure-flags)
>             `(list "--host=i686-pc-gnu"
>
>                    ;; nscd fails to build for GNU/Hurd:
>                    ;; 
> <https://lists.gnu.org/archive/html/bug-hurd/2014-07/msg00006.html>.
>                    ;; Disable it.
>                    "--disable-nscd"
>
>                    ,@(filter (lambda (flag)
>                                (not (or (string-prefix? "--with-headers=" 
> flag)
>                                         (string-prefix? "--enable-kernel=" 
> flag))))
>                              original-configure-flags)))

The code above didn't work, for two reasons:

(1) 'original-configure-flags' is not actually a list of flags, but
    rather a scheme expression that evaluates to a list of flags.

(2) Evaluating 'original-configure-flags' fails in this context, because
    it includes the expression (from our glibc package)

            (string-append "--with-headers="
                           (assoc-ref %build-inputs "linux-headers")
                           "/include")

    but in this glibc/hurd package, there is no 'linux-headers' input,
    so the 'assoc-ref' returns #f and 'string-append' fails.

After a few iterations on IRC, I proposed this code which seems to work:

--8<---------------cut here---------------start------------->8---
       ((#:configure-flags original-configure-flags)
        `(append (list "--host=i686-pc-gnu"

                       ;; nscd fails to build for GNU/Hurd:
                       ;; 
<https://lists.gnu.org/archive/html/bug-hurd/2014-07/msg00006.html>.
                       ;; Disable it.
                       "--disable-nscd")
                 (filter (lambda (flag)
                           (not (or (string-prefix? "--with-headers=" flag)
                                    (string-prefix? "--enable-kernel=" flag))))
                         ;; Evaluate 'original-configure-flags' in a
                         ;; lexical environment that has a dummy
                         ;; "linux-headers" input, to prevent errors.
                         (let ((%build-inputs `(("linux-headers" "@DUMMY@")
                                                ,@%build-inputs)))
                           ,original-configure-flags))))
--8<---------------cut here---------------end--------------->8---

but obviously it's a bit gross.  Ideally, we consider consider having a
'glibc/base' package that is inherited by both 'glibc/linux' and
'glibc/hurd'.  The base package would not add any linux stuff, on the
theory that it is easier and cleaner to add kernel-specific stuff than
to remove it.

     Thoughts?
        Mark