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Date:   Wed, 18 Oct 2023 03:12:41 +0200 (CEST)
From:   Jan Engelhardt <jengelh@inai.de>
To:     =?UTF-8?Q?Michal_Such=C3=A1nek?= <msuchanek@suse.de>
cc:     Masahiro Yamada <masahiroy@kernel.org>,
        linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        Nicolas Schier <nicolas@fjasle.eu>,
        linux-modules@vger.kernel.org, Takashi Iwai <tiwai@suse.com>,
        Lucas De Marchi <lucas.de.marchi@gmail.com>,
        =?UTF-8?Q?Michal_Koutn=C3=BD?= <mkoutny@suse.com>,
        Jiri Slaby <jslaby@suse.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH rebased] kbuild: rpm-pkg: Fix build with non-default
 MODLIB
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On Tuesday 2023-10-17 17:10, Michal Suchánek wrote:
>
>> In my system (Ubuntu), I see the directory paths
>> 
>> /usr/aarch64-linux-gnu/lib/
>> /usr/i686-linux-gnu/lib/
>> /usr/x86_64-linux-gnu/lib/
>> 
>> If there were such a crazy distro that supports multiple kernel arches
>> within a single image, modules might be installed:
>> /usr/x86_64-linux-gnu/lib/module/<version>/
>
>For me it's /usr/lib/i386-linux-gnu/.
>
>Did they change the scheme at some point?

It's a complicated mumble-jumble. Prior art exists as in:

 /opt/vendorThing/bin/...
 /usr/X11R6/lib/libXi.so.6 [host binary]
 /usr/x86_64-w64-mingw32/bin/as [host binary]
 /usr/x86_64-w64-mingw32/sys-root/mingw/bin/as.exe [foreign binary]
 /usr/platform/SUNW,Ultra-2/lib/libprtdiag_psr.so.1 [looks foreign]

The use of suffix-based naming must have been established sometime
near the end of the 90s or the start of 2000s as the first biarch
Linux distros emerged. Probably in gcc or glibc sources one will find
the root of where the use of suffix identifiers like /usr/lib64
started. Leaves the question open "why".