In source file my_init.c, there is a call

setlocale(LC_CTYPE, ""); /* To get right sortorder */

This will eventually set the locale to system locale. C run-time functions uses this information for validating/comparing parameters. In my understanding this is dangerous thing to do for a UTF-8 client. As UTF-8 doesnt depend on any locale, the passed string might have some character sequence that the string functions consider improper. This is resulting in exception.

I checked the mariadbclient source and couldn't find any relevent functions which uses strcmp and depends on locale. So I think it is not doing anything the comment says, correct me if I am wrong.

On a side note I believe MariaDB client shouldn't have set the locale on the whole, it should have rather used the locale enabled versions of string functions for its internal use.