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-10.0.10/scripts/mysql_config.sh.p10 mariadb-10.0.10/scripts/mysql_config.sh
--- mariadb-10.0.10/scripts/mysql_config.sh.p10	2014-03-30 19:56:39.000000000 +0200
+++ mariadb-10.0.10/scripts/mysql_config.sh	2014-04-07 18:54:19.601390650 +0200
@@ -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@'