MDEV-37197 Install PAM modules and systemd units in /usr/lib (not /lib)

Since Fedora 17 and about 2012, the directory /lib has been a symlink to
/usr/lib. Debian started a similar migration in 2019. Nowadays all major
Linux distributions have a merged /usr, and the canonical location for
files should be /usr/lib instead of just /lib.

The location of PAM modules and systemd files is the last remaining
`*_DEB` variables should fully complete the usr merge migration.

References:
- https://fedoraproject.org/wiki/Features/UsrMove
- https://www.debian.org/releases/bookworm/amd64/release-notes/ch-information.en.html#a-merged-usr-is-now-required
- https://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge/

Author: ottok

cmake/install_layout.cmake

@@ -196,10 +196,10 @@ SET(INSTALL_MYSQLDATADIR_DEB            "/var/lib/mysql")
 
 SET(INSTALL_RUNDATADIR_DEB              "/run/mysqld")
 SET(INSTALL_UNIX_ADDRDIR_DEB            "${INSTALL_RUNDATADIR_DEB}/mysqld.sock")
-SET(INSTALL_SYSTEMD_UNITDIR_DEB         "/lib/systemd/system")
+SET(INSTALL_SYSTEMD_UNITDIR_DEB         "/usr/lib/systemd/system")
 SET(INSTALL_SYSTEMD_SYSUSERSDIR_DEB     "/usr/lib/sysusers.d")
 SET(INSTALL_SYSTEMD_TMPFILESDIR_DEB     "/usr/lib/tmpfiles.d")
-SET(INSTALL_PAMDIR_DEB                  "/lib/${CMAKE_CXX_LIBRARY_ARCHITECTURE}/security")
+SET(INSTALL_PAMDIR_DEB                  "/usr/lib/${CMAKE_CXX_LIBRARY_ARCHITECTURE}/security")
 SET(INSTALL_PAMDATADIR_DEB              "/etc/security")
 
 #

debian/mariadb-server.install

@@ -6,14 +6,14 @@ debian/additions/source_mariadb.py usr/share/apport/package-hooks
 etc/apparmor.d/usr.sbin.mariadbd
 etc/logrotate.d/mariadb
 etc/security/user_map.conf
-lib/*/security/pam_user_map.so
-lib/systemd/system/mariadb@bootstrap.service.d/use_galera_new_cluster.conf
-lib/systemd/system/mariadb-extra@.socket
-lib/systemd/system/mariadb.service
-lib/systemd/system/mariadb@.service
-lib/systemd/system/mariadb@.socket
-lib/systemd/system/mysql.service
-lib/systemd/system/mysqld.service
+usr/lib/*/security/pam_user_map.so
+usr/lib/systemd/system/mariadb@bootstrap.service.d/use_galera_new_cluster.conf
+usr/lib/systemd/system/mariadb-extra@.socket
+usr/lib/systemd/system/mariadb.service
+usr/lib/systemd/system/mariadb@.service
+usr/lib/systemd/system/mariadb@.socket
+usr/lib/systemd/system/mysql.service
+usr/lib/systemd/system/mysqld.service
 support-files/rpm/enable_encryption.preset etc/mysql/mariadb.conf.d/99-enable-encryption.cnf.preset
 usr/lib/tmpfiles.d/mariadb.conf
 usr/bin/aria_chk

debian/not-installed

@@ -4,8 +4,8 @@ etc/mysql/mariadb.conf.d/client.cnf # Debian packaging uses files from debian/ad
 etc/mysql/mariadb.conf.d/enable_encryption.preset # Debian packaging uses files from debian/additions/mariadb.cnf.d/
 etc/mysql/mariadb.conf.d/mysql-clients.cnf # Debian packaging uses files from debian/additions/mariadb.cnf.d/
 etc/mysql/mariadb.conf.d/server.cnf # Debian packaging uses files from debian/additions/mariadb.cnf.d/
-lib/systemd/system/mariadb-extra.socket # Installed by rules file
-lib/systemd/system/mariadb.socket # Installed by rules file
+usr/lib/systemd/system/mariadb-extra.socket # Installed by rules file
+usr/lib/systemd/system/mariadb.socket # Installed by rules file
 usr/bin/mariadb-embedded # Shipping the embedded server in distro packaging does not make sense
 usr/bin/mysql_config # Debian packaging has mysql_config as symlink to mariadb_config
 usr/bin/mysql_embedded # Symlink to mariadb-embedded which is intentionally not included