get source from MariaDB
extract to /usr/local/src/mariadb

Modular configure (usually you need to load plugins with my.cnf) i am using this one.

./configure --with-extra-charsets=all --localstatedir=/var/db/mysql

OR

Build With Plugin

./configure --with-extra-charsets=all  --with-plugin-maria --with-plugin-xtradb --localstatedir=/var/db/mysql

OR

Static Build as suggested by MariaDB wiki.

./configure --prefix=/usr/local/mysql --enable-assembler \
--with-extra-charsets=all  --enable-thread-safe-client  --with-big-tables \
--with-plugin-maria --with-maria-tmp-tables --with-plugin-xtradb \
--with-mysqld-ldflags=-static --with-client-ldflags=-static --with-readline \
--with-ssl --with-plugins=max-no-ndb --with-embedded-server --with-libevent \
--with-mysqld-ldflags=-all-static  --with-client-ldflags=-all-static \
--with-zlib-dir=bundled --enable-local-infile

Now run “make -j4” and “make install” – will install it on system.

You can simply use script provided with port version of mysql.
Just in case if you dont have it, use below.

| /usr/local/etc/rc.d/mysql

#!/bin/sh
#
# $FreeBSD: ports/databases/mysql51-server/files/mysql-server.sh.in,v 1.6 2008/07/30 06:11:16 ale Exp $
#
 
# PROVIDE: mysql
# REQUIRE: LOGIN
# KEYWORD: shutdown
 
#
# Add the following line to /etc/rc.conf to enable mysql:
# mysql_enable (bool):  Set to "NO" by default.
#                       Set it to "YES" to enable MySQL.
# mysql_limits (bool):  Set to "NO" by default.
#                       Set it to yes to run `limits -e -U mysql`
#                       just before mysql starts.
# mysql_dbdir (str):    Default to "/var/db/mysql"
#                       Base database directory.
# mysql_args (str):     Custom additional arguments to be passed
#                       to mysqld_safe (default empty).
#
 
. /etc/rc.subr
 
name="mysql"
rcvar=`set_rcvar`
 
load_rc_config $name
 
: ${mysql_enable="NO"}
: ${mysql_limits="NO"}
: ${mysql_dbdir="/var/db/mysql"}
: ${mysql_args=""}
 
mysql_user="mysql"
mysql_limits_args="-e -U ${mysql_user}"
pidfile="${mysql_dbdir}/`/bin/hostname`.pid"
command="/usr/local/bin/mysqld_safe"
command_args="--defaults-extra-file=${mysql_dbdir}/my.cnf --user=${mysql_user} --datadir=${mysql_dbdir} --pid-file=${pidfile} ${mysql_args} > /dev/null 2>&1 &"
procname="/usr/local/libexec/mysqld"
start_precmd="${name}_prestart"
start_postcmd="${name}_poststart"
mysql_install_db="/usr/local/bin/mysql_install_db"
mysql_install_db_args="--ldata=${mysql_dbdir}"
 
mysql_create_auth_tables()
{
        eval $mysql_install_db $mysql_install_db_args >/dev/null 2>/dev/null
        [ $? -eq 0 ] && chown -R ${mysql_user}:${mysql_user} ${mysql_dbdir}
}
 
mysql_prestart()
{
        if [ ! -d "${mysql_dbdir}/mysql/." ]; then
                mysql_create_auth_tables || return 1
        fi
        if checkyesno mysql_limits; then
                eval `/usr/bin/limits ${mysql_limits_args}` 2>/dev/null
        else
                return 0
        fi
}
 
mysql_poststart()
{
        local timeout=15
        while [ ! -f "${pidfile}" -a ${timeout} -gt 0 ]; do
                timeout=$(( timeout - 1 ))
                sleep 1
        done
        return 0
}
 
run_rc_command "$1"