Thank you for the bug report and your patch.

Please note that gpgrt_spawn_actions_set_envvars is W32 specific API in libgpg-error. Currently, the behavior with ASCII string is defined.
The patch is an answer in future if we want to extend the semantics supporting UTF-8.

Here is my attempt:

Use of execve is better (avoiding use of environ).

Fixed in: rA69069bc63e6b: Remove an declaration for an unused function

I re-consider. Adding arguments to existing gcry_kem_keypair is not good since it introduces API break.
Instead, I add gcry_kem_genkey with additional arguments (which can be used for deterministic key generation).

I can replicate the problem.

I was confused. We already have KAT for decap in t-mlkem.c.

• https://github.com/C2SP/CCTV/tree/main/ML-KEM
• https://github.com/usnistgov/ACVP-Server/tree/master/gen-val/json-files

That's my badness.
I noticed by the CI at https://gitlab.com/redhat-crypto/libgcrypt/libgcrypt-mirror

The socklen_t use are now being fixed in newer POSIX Issue 8, 2024.
https://www.man7.org/linux/man-pages/man3/socklen_t.3type.html

My summary here:

• Use of winepath by libtool is correct way for semi-hosted environment to run tests built by cross-build.
• (cross-)Build itself is possible with no winepath (or winepath -> /bin/false), if you don't need make check with semi-hosted environment.
• I don't see that it's too slow, these days. My environment is bookworm Debian (having Wine 8.0 something).

Fixed in: rG1e6b96577f68: gpg: Fix agent_probe_any_secret_key.

Thank you for your report.

Pushed the change: rGaf6c47b2910f: common,kbx,tests: Clean up the PIPE function API.

Push the change: rG953dd67368ce: Use gpgrt_process_spawn API from libgpg-error.
Please test.

Thank you for your report. We are about to migrate to use the gpgrt_spawn_process API.
(In our development history, it was originally implemented and tested as gnupg_spawn_process API and moved to libgpg-error.)

Thank you for the patch.

Thank you for your report, good catch.
It's introduced by the commit: rC909daa700e4b: blake2: add AVX512 accelerated implementations
And the bug is there since then.

Fixed in rG01fa318be0f8: scd: Fix how scdaemon pipe server finishes.

Asking a change of gpgme would need more time... So, I decided to change gpg-agent side.
gpg-agent part was done in: rGb3f1f2cd192b: agent: Handle SCD DEVINFO --watch command in a special way.

scdaemon part was done in: rG36d8cffc6cd2: scd: Finish DEVINFO --watch command on input close.

Did some experiment and I concluded (for now) that new command for gpg-agent would not be needed.
Instead, it might be better doing following in GPGME.

Pushed the change to master. Please test.
rCbb0895bbb7c6: m4: Fix acinclude.m4 for underscore detection in the symbol.

Thank you for the report.