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From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: [PATCH 06/13] build: Generate man pages after compiling guile
	objects.
Date: Tue, 26 Jan 2016 17:52:38 +0100
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In-Reply-To: <1453666771-16869-7-git-send-email-mthl@gnu.org> (Mathieu
	Lirzin's message of "Sun, 24 Jan 2016 21:19:24 +0100")
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To: Mathieu Lirzin <mthl@gnu.org>
Cc: guix-devel@gnu.org

Mathieu Lirzin <mthl@gnu.org> skribis:

> This improves compilation speed since scripts are not compiled twice.
> When building with =E2=80=98make -j4=E2=80=98 from a clean repository on =
an Intel
> i5-2540M, the time of compilation gets from:
>
> real	5m7.220s
> user	18m49.788s
> sys	0m12.964s
>
> down to:
>
> real	2m20.820s
> user	7m25.992s
> sys	0m7.464s
>
> * configure.ac (BUILD_FROM_GIT): New Automake conditional.
> * doc.am (SUBCOMMANDS): Delete variable.
> (dist_man1_MANS): List all subcommands man pages.
> (doc/guix.1): Build only if BUILD_FROM_GIT.  Depend on 'scripts/guix'
> instead of all subcommands.
> [BUILD_DAEMON] (doc/guix-daemon): Likewise.  Replace the
> 'nix/nix-daemon/guix-daemon.cc' prerequisite with 'guix-daemon'.
> [BUILD_FROM_GIT] (gen_man): New variable.
> [BUILD_FROM_GIT] (doc/guix-%.1): New target.
> (CLEANFILES) [BUILD_FROM_GIT]: Add $(dist_man1_MANS).

I like the speedup, but not the =E2=80=98BUILD_FROM_GIT=E2=80=99 approach. =
 :-)
It reminds me of maintainer-mode and all its warts (info "(automake)
maintainer-mode").

Namely, I think it=E2=80=99s best to have the help2man rule always triggered
whenever the corresponding .scm file is newer, rather than have it
triggered or not based on a guess of what the user wants/can do.

Having said that, I=E2=80=99m not sure what to do.  Commit 0af3f404 reverte=
d the
original approach, which was to depend on .go files (and obviously
wouldn=E2=80=99t work as we want.)

So we want to delay the build of man pages without making the dependency
on build products explicit.  Hmm, not sure what can be done.

Thoughts?

Ludo=E2=80=99.