build: Allow build with no Kyber.
* configure.ac (GCRYPT_PUBKEY_CIPHERS): It's kyber.lo. * tests/Makefile.am (tests_bin): [USE_KYBER]: Add t-mlkem only when USE_KYBER. * tests/t-kem.c: Allow building with no Kyber.
Cherry-picked master commit of:
f2b7d7862ff91457966b7f14ce92bf15655766cd
- Fixes-commit: 7eaa43bf0931494afccbd413d83a3010aa80cee0
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>