Don't guess basedir in mysql_config; we place it under _libdir because
of multilib conflicts, so use rather configured @prefix@ path directly.

diff -up mariadb-5.5.29/scripts/mysql_config.sh.basedir mariadb-5.5.29/scripts/mysql_config.sh
--- mariadb-5.5.29/scripts/mysql_config.sh.basedir	2013-02-28 09:39:26.628440114 +0100
+++ mariadb-5.5.29/scripts/mysql_config.sh	2013-02-28 09:39:40.613439729 +0100
@@ -76,7 +76,7 @@ get_full_path ()
 
 me=`get_full_path $0`
 
-basedir=`echo $me | sed -e 's;/bin/mysql_config;;'`
+basedir='@prefix@'
 
 ldata='@localstatedir@'
 execdir='@libexecdir@'