diff --git a/meson.build b/meson.build
index be532d1cc79..2a6e45b79a7 100644
--- a/meson.build
+++ b/meson.build
@@ -3247,6 +3247,8 @@ test_env = environment()
 test_initdb_template = meson.build_root() / 'tmp_install' / 'initdb-template'
 test_env.set('PG_REGRESS', pg_regress.full_path())
 test_env.set('REGRESS_SHLIB', regress_module.full_path())
+# for Cluster.pm's portlock logic
+test_env.set('top_builddir', meson.build_root())
 
 # Test suites that are not safe by default but can be run if selected
 # by the user via the whitespace-separated list in variable PG_TEST_EXTRA.
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index 9c210682c79..6cd32adbf74 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -169,9 +169,7 @@ INIT
 	$portdir = $ENV{PG_TEST_PORT_DIR};
 	# Otherwise, try to use a directory at the top of the build tree
 	# or as a last resort use the tmp_check directory
-	my $build_dir =
-		 $ENV{MESON_BUILD_ROOT}
-	  || $ENV{top_builddir}
+	my $build_dir = $ENV{top_builddir}
 	  || $PostgreSQL::Test::Utils::tmp_check;
 	$portdir ||= "$build_dir/portlock";
 	$portdir =~ s!\\!/!g;