package/mariadb: patch mariadb_config to add sysroot path

package/mariadb: patch mariadb_config to add sysroot path

This patch adds @CMAKE_SYSROOT@ to mariadb_config.c.in. Without it,
mariadb_config and mysql_config incorrectly returns host paths for
include paths and library paths.

The patch has been accepted upstream at
https://github.com/mariadb-corporation/mariadb-connector-c/commit/b787c0d69cc00af98cd4ee5bc205e1c7ddaf427a

Reported-by: Alexey Lukyanchuk <skif@skif-web.ru>
Signed-off-by: Ryan Coe <bluemrp9@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>