Determine mysql / mariadb command name for dbinterop tests

In more recent versions of mariadb, the mysql commmands (mysql, mysqldump) etc. are not present anymore.
Instead, mariadb and mariadb-dump need to be used.

Makefile

@@ -38,8 +38,10 @@ RELEASE_VERSION ?= $(shell git tag --points-at HEAD)
 # The following environment variables are assumed for MYSQL:
 #   - MYSQL_PASSWORD: Password of the MySQL root user
 #   - MYSQL_CMD_PREFIX: Prefix to use for all mysql commands (intended use: docker exec)
-MYSQL     := $(MYSQL_CMD_PREFIX) mysql -u root -p"$$MYSQL_PASSWORD"
-MYSQLDUMP := $(MYSQL_CMD_PREFIX) mysqldump -u root -p"$$MYSQL_PASSWORD"
+MYSQLCMD := $(shell $(MYSQL_CMD_PREFIX) sh -c 'which mariadb mysql | head -n 1')
+MYSQLDUMPCMD := $(shell $(MYSQL_CMD_PREFIX) sh -c 'which mariadb-dump mysqldump | head -n 1')
+MYSQL     := $(MYSQL_CMD_PREFIX) $(MYSQLCMD) -u root -p"$$MYSQL_PASSWORD"
+MYSQLDUMP := $(MYSQL_CMD_PREFIX) $(MYSQLDUMP) -u root -p"$$MYSQL_PASSWORD"
 
 # POSTGRES_CMD_PREFIX can be used to run the command inside a docker container
 # For simplicity, we assume an isolated test database that we can directly access as the postgres user with no sensitive password