cannot build rubygem-mysql2 with MariaDB 10.11

I am trying to build Redmine 5.1 which needs databases/rubygem-mysql2 
but it failed with the following error:

Using mysql_config at /usr/local/bin/mysql_config
-----
checking for mysql.h... no
checking for mysql/mysql.h... no
-----
mysql.h is missing. You may need to 'sudo apt-get install 
libmariadb-dev', 'sudo apt-get install libmysqlclient-dev' or 'sudo yum 
install mysql-devel', and try again.
-----
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details. 
You may
need configuration options.


I am building it in the Poudriere on FreeBSD 13.2 with non-default 
versions of python and mysql:
DEFAULT_VERSIONS=apache=2.4 perl5=5.36 mysql=10.11m php=8.3 python=3.11 
python3=3.11 pgsql=13 bdb=5 IMAGEMAGICK=7-nox11

I think the MariaDB 10.11 causes some problem to rubygem-mysql2 
configure, but I don't know what is wrong. MariaDB installed mysql.h as 
usual.

Does anybody built rubygem-mysql2 with MariaDB 10.11?

I can create PR in bugzilla with a full build log from the Poudriere if 
somebody is interested.

Kind regards
Miroslav Lachman