Re: libxkbcommon version-script detection

From: Dimitry Andric <dim_at_FreeBSD.org>
Date: Fri, 10 Jan 2025 12:28:49 UTC
On 10 Jan 2025, at 12:56, Dimitry Andric <dim@FreeBSD.org> wrote:
> 
> On 10 Jan 2025, at 12:20, Peter Blok <pblok@bsd4all.org> wrote:
>> 
>> Test works ok when using clang18 from ports
>> 
>>> On 10 Jan 2025, at 11:19, Dimitry Andric <dim@FreeBSD.org> wrote:
>>> 
>>> On 10 Jan 2025, at 10:22, Peter Blok <pblok@bsd4all.org> wrote:
>>>> 
>>>> I have recompiled x11/libxkbcommon and it fails to detect if the compiler/linker supports versioned symbols. As a result other code expecting the versioned symbol to exist, fail to link.
>>>> 
>>>> C compiler for the host machine: cc (clang 19.1.5 "FreeBSD clang version 19.1.5 (https://github.com/llvm/llvm-project.git llvmorg-19.1.5-0-gab4b5a2db582)")
>>>> C linker for the host machine: cc ld.lld 19.1.5
>>>> 
>>>> Below the meson.build check. If I force have_version_script to true, the versioned symbols are created and other code links fine.
>>>> 
>>>> # Supports -Wl,--version-script?
>>>> have_version_script = cc.links(
>>>> 'int main(){}',
>>>> args: '-Wl,--undefined-version,--version-script=' + meson.current_source_dir()/'xkbcommon.map',
>>>> name: '-Wl,--version-script',
>>>> )
>>>> 
>>>> Below the output for the test.
>>>> 
>>>> Checking if "-Wl,--version-script" : links: NO
>>>> 
>>>> If I create test.c with content "int main(){}” and compile it manually with the same flags AFAIK, it compiles ok. No errors.
>>>> 
>>>> However when I capture "make configure" with ktrace, it fails with the error below.
>>>> 
>>>> ld: error: non-exported symbol 'environ' in '/usr/lib/crt1.o' is referenced by DSO '/lib/libc.so.7'
>>>>     ld: error: non-exported symbol '__progname' in '/usr/lib/crt1.o' is referenced by DSO '/lib/libc.so.7'
>>>>     cc: error: linker command failed with exit code 1 (use -v to see invocation)
>>>> 
>>>> What flags need to be added in meson.build to allow it to work?
>>>> 
>>>> BTW This is on recent stable, but I suspect it fails the same way on current which I do not run at the moment.
>>> 
>>> It works just fine on -CURRENT:
>>> 
>>> ...
>>> Checking if "-Wl,--version-script" : links: YES
>>> 
>>> Not sure what is going wrong in your environment. Is this stable/14?
> 
> It appears to help when the lines:
> 
> local:
>    *;
> 
> are removed from /wrkdirs/usr/ports/x11/libxkbcommon/work/libxkbcommon-1.7.0/xkbcommon.map. Apparently on main, environ and __progname are slightly different.
> 
> In any case, the "local: *;" thing has caused problems before, so maybe it's better to get rid of it.

Here's a better patch, that can also be upstreamed. It avoids the whole problem of trying to use the "full" xkbcommon.map during meson tests.

-Dimitry