Hi,
What kind of a problem with rpm/deb does the current state of things (links) cause?
Traditionally, packages are broken out into -dev, -lib, etc. -dev contains the linking portions (lib/.so, lib/.la, lib/.a, include/) that are only required for building software that links to the given package. However, due to the incorrect way in which libmysqlclient_r is symlinked, one has to delete and correctly link it to create a proper dev package. It would be simpler if mariadb correctly created libmysqlclient_r to start with, so games don't have to be played to create a proper -dev package.
Like http://packages.ubuntu.com/trusty/amd64/libssl-dev/filelist, for example
Assigning to serg for further consideration.
As I understand, we somehow manage to build dev packages, but maybe we aren't doing it the right way. Also, I don't remember otto complaining about it – maybe he has already fixed it in his tree?
I bet any linked software just ends up pointing to libmysqlclient.so.18.0.0, so it becomes moot as far as a dev vs lib package, as long as libmysqlcient.so.18.0.0 is in the lib package. I think this can be closed out then, although it still is really odd looking. 
For debian, I know they're playing games, because they renamed the libraries to libmariadbclient* instead of libmysqlclient, so it's hard to base anything as to what is "correct" off their packages.
elenst Due to reasons explained in MDEV-5482 there is no libmysqlclient nor libmariadbclient package in Debian anymore, instead the LGPL licenced MariaDB Client for C is provided. It is not a perfect solution but best compromise at the moment.
This isn't easy to do with our cmake files. I suggest to keep symlinks the old way in 10.0 and drop libmysqlclient_r completely in 10.1.