ldmud: patch mysql configure script detection

The upstream `configure.ac`'s `AC_LANG_PROGRAM` for mysql feature
detection seems to be incompatible with the `mariadb-connector-c`
package, resulting in support not being detected.

Digging in to the `config.log` we can see it's a type mismatch error
from the test program `.c`:

```
configure:11661: checking for mySQL
configure:11694: gcc -c -g -O2 -fwrapv -I/usr/inet6/include -I/nix/store/ya8wpj6dqz39024v6xrv504i9kyidpil-mariadb-connector-c-3.1.21-dev/include/mysql conftest.c >&5
conftest.c: In function 'foo':
conftest.c:90:12: error: returning 'MYSQL *' {aka 'struct st_mysql *'} from a function with incompatible return type 'struct MYSQL *' [-Wincompatible-pointer-types]
90 |     return &var;
|            ^~~~
```

This commit resolves the issue locally by applying a small patch.

0 files changed, 0 insertions, 0 deletions