There are few functions which were added in upstream p11-kit 0.23.3.
And there are compilation failures with older versions.

src/p11_child/p11_child_openssl.c: In function 'get_pkcs11_uri':
src/p11_child/p11_child_openssl.c:87:12: error: implicit declaration of function 'p11_kit_uri_get_slot_info' [-Werror=implicit-function-declaration]
memcpy(p11_kit_uri_get_slot_info(uri), slot_info, sizeof(CK_SLOT_INFO));
^

src/p11_child/p11_child_openssl.c:88:5: error: implicit declaration of function 'p11_kit_uri_set_slot_id' [-Werror=implicit-function-declaration]
p11_kit_uri_set_slot_id(uri, slot_id);
^

src/p11_child/p11_child_openssl.c: In function 'do_card':
src/p11_child/p11_child_openssl.c:767:35: error: implicit declaration of function 'p11_kit_uri_get_slot_id' [-Werror=implicit-function-declaration]
uri_slot_id = p11_kit_uri_get_slot_id(uri);
^
src/p11_child/p11_child_openssl.c:770:32: error: implicit declaration of function 'p11_kit_uri_match_slot_info' [-Werror=implicit-function-declaration]
|| p11_kit_uri_match_slot_info(uri, &info) != 1) {
^