If you are compiling MariaDB yourself and you need the compat RPM, you need to download the latest MariaDB-shared-5.3 RPM from http://downloads.mariadb.org/MariaDB/5.3.7/
Place the file OUTSIDE of you source directory.
Directory listing:
mariadb-5.5.25 (source directory)
mariadb-5.5.25.tar.gz
MariaDB-shared-5.3.7-116.el5.x86_64.rpm