MDEV-23538: Rename mariadb.pc to mariadb-server-embedded.pc to avoid confusion

Change so that the client library config can be accessed using the name
mariadb.pc (or libmariadb.pc).

Rename old mariadb.pc to mariadb-embedded-server.pc to better indicate
that the config is for the daemon build, not client.

Also keep/include names with 'lib' as symlinks, as it aligns with how most
of *.pc files are named in general.

In downstream Debian we already ship the libmariadb.pc as mariadb.pc:
https://salsa.debian.org/mariadb-team/mariadb-10.5/-/commit/2f183af990fbe1cfa8c343998c7640f45f45368b

After this change we would have for the files:
- mariadb.pc for client (with libmariadb.pc as symlink)
- mariadb-embedded-sever.pc for server (with libmariadbd.pc as symlink)

Author: ottok

debian/libmariadb-dev.install

@@ -29,6 +29,7 @@ usr/lib/*/libmariadbclient.a
 usr/lib/*/libmariadbclient.so
 usr/lib/*/libmysqlservices.a
 usr/lib/*/pkgconfig/libmariadb.pc
+usr/lib/*/pkgconfig/mariadb.pc
 usr/share/aclocal/mysql.m4
 usr/share/man/man1/mariadb_config.1
 usr/share/man/man1/mysql_config.1

debian/libmariadbd-dev.install

@@ -3,3 +3,5 @@ usr/lib/*/libmariadbd.a
 usr/lib/*/libmariadbd.so
 usr/lib/*/libmysqld.a
 usr/lib/*/libmysqld.so
+usr/lib/*/pkgconfig/libmariadbd.pc
+usr/lib/*/pkgconfig/mariadb-embedded-server.pc

debian/rules

@@ -161,6 +161,17 @@ override_dh_auto_install:
 	# Rename and install AppArmor profile
 	install -D -m 644 debian/apparmor-profile $(TMP)/etc/apparmor.d/usr.sbin.mariadbd
 
+	# Rename mariadb.pc as mariadb-embedded-server.pc as to be more descriptive
+	mv -v $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/pkgconfig/mariadb.pc $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/pkgconfig/mariadb-embedded-server.pc
+	# Keep libmariadbd.pc around for backwards compatibility as all Debian users
+	# have had it for embedded server since April 2021
+	ln -sf mariadb-embedded-server.pc $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/pkgconfig/libmariadbd.pc
+
+	# Rename libmariadb.pc as mariadb.pc as it better fits the client library,
+	# and keep old libmariadb.pc as symlink for backwards compatibility
+	mv -v $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/pkgconfig/libmariadb.pc $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/pkgconfig/mariadb.pc
+	ln -sf mariadb.pc $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/pkgconfig/libmariadb.pc
+
 	# Install libmariadbclient18 compatibility links
 	ln -s libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmariadbclient.so
 	ln -s libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmariadbclient.so.18