--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -36,6 +36,10 @@
 
 # use the sample file from the temp install
 my $share_dir = $node->config_data('--sharedir');
+# XXX-Patched: --sharedir returns /usr/share/...
+if (-d "../../../../tmp_install") {
+	$share_dir = "../../../../tmp_install" . $share_dir
+}
 my $sample_file = "$share_dir/postgresql.conf.sample";
 
 # List of all the GUCs found in the sample file.