MDEV-33492: mysql_install_db fails when baseurl is set

auth_map.so isn't guaranteed to be available. Fedora packages it
separately.

The --base-dir path of mysql_install_db.sh seems to contain
historicial heuristics that have been replaced on other branches
of the script.

We attempt to do the same here placing the basedir original paths
so that all components are absolute.

scripts/mysql_install_db.sh

@@ -344,33 +344,13 @@ then
   pamtooldir="$builddir/plugin/auth_pam"
 elif test -n "$basedir"
 then
-  bindir="$basedir/bin" # only used in the help text
-  resolveip=`find_in_dirs resolveip @resolveip_locations@`
-  if test -z "$resolveip"
-  then
-    cannot_find_file resolveip @resolveip_locations@
-    exit 1
-  fi
-  mysqld=`find_in_dirs mariadbd @mysqld_locations@`
-  if test -z "$mysqld"
-  then
-      cannot_find_file mariadbd @mysqld_locations@
-      exit 1
-  fi
-  langdir=`find_in_dirs --dir errmsg.sys @errmsg_locations@`
-  if test -z "$langdir"
-  then
-    cannot_find_file errmsg.sys @errmsg_locations@
-    exit 1
-  fi
-  srcpkgdatadir=`find_in_dirs --dir fill_help_tables.sql @pkgdata_locations@`
-  buildpkgdatadir=$srcpkgdatadir
-  if test -z "$srcpkgdatadir"
-  then
-    cannot_find_file fill_help_tables.sql @pkgdata_locations@
-    exit 1
-  fi
-  plugindir=`find_in_dirs --dir auth_pam.so $basedir/lib*/plugin $basedir/lib*/mysql/plugin $basedir/lib/*/mariadb19/plugin`
+  bindir="$basedir/@INSTALL_BINDIR@"
+  resolveip="$bindir/resolveip"
+  mysqld="$basedir/@INSTALL_SBINDIR@/mariadbd"
+  langdir="$basedir/share/english"
+  srcpkgdatadir="$basedir/@INSTALL_MYSQLSHAREDIR@"
+  buildpkgdatadir="$basedir/@INSTALL_MYSQLSHAREDIR@"
+  plugindir="$basedir/@INSTALL_PLUGINDIR@"
   pamtooldir=$plugindir
 # relative from where the script was run for a relocatable install
 elif test -n "$dirname0" -a -x "$rel_mysqld" -a ! "$rel_mysqld" -ef "@sbindir@/mariadbd"