Re: [PATCH bpf v3] resolve_btfids: Fix linker flags detection

[Paul Chaignon <paul.chaignon@gmail.com>]

On Wed, Mar 04, 2026 at 05:47:30PM -0800, Ihor Solodrai wrote:
> The "|| echo -lzstd" default makes zstd an unconditional link
> dependency of resolve_btfids. On systems where libzstd-dev is not
> installed and pkg-config fails, the linker fails:
> 
>   ld: cannot find -lzstd: No such file or directory
> 
> libzstd is a transitive dependency of libelf, so the -lzstd flag is
> strictly necessary only for static builds [1].
> 
> Remove ZSTD_LIBS variable, and instead set LIBELF_LIBS depending on
> whether the build is static or not. Use $(HOSTPKG_CONFIG) as primary
> source of the flags list.
> 
> Also add a default value for HOSTPKG_CONFIG in case it's not built via
> the toplevel Makefile. Pass it from selftests/bpf too.
> 
> [1] https://lore.kernel.org/bpf/4ff82800-2daa-4b9f-95a9-6f512859ee70@linux.dev/
> 
> Reported-by: BPF CI Bot (Claude Opus 4.6) <bot+bpf-ci@kernel.org>
> Reported-by: Vitaly Chikunov <vt@altlinux.org>
> Closes: https://lore.kernel.org/bpf/aaWqMcK-2AQw5dx8@altlinux.org/
> Fixes: 4021848a903e ("selftests/bpf: Pass through build flags to bpftool and resolve_btfids")
> Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
> ---

Reviewed-by: Paul Chaignon <paul.chaignon@gmail.com>

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