Correctly link mysqlclient.pc to mariadb.pc under multi-arch support

debian/control

@@ -7,6 +7,7 @@ Build-Depends: bison,
                cmake (>= 2.7),
                debhelper (>= 9),
                dh-apparmor,
+               dh-exec,
                dh-systemd,
                gdb,
                libaio-dev [linux-any],

debian/libmariadb-dev-compat.links

+#!/usr/bin/dh-exec
 usr/bin/mariadb_config usr/bin/mysql_config
 usr/include/mariadb usr/include/mysql
-usr/share/pkgconfig/mariadb.pc usr/share/pkgconfig/mysqlclient.pc
+usr/lib/${DEB_HOST_MULTIARCH}/pkgconfig/mariadb.pc usr/lib/${DEB_HOST_MULTIARCH}/pkgconfig/mysqlclient.pc