diff --git a/Makefile.meson b/Makefile.meson
index 7e069b88..326c051e 100644
--- a/Makefile.meson
+++ b/Makefile.meson
@@ -1,4 +1,4 @@
-## Copyright (C) 2008-2021 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+## Copyright (C) 2008-2022 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
 ##
 ## This program is free software; you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
@@ -20,11 +20,18 @@ NINJA    ?= ninja
 BUILDDIR ?= $(CURDIR)/build
 MESON    ?= meson
 
+
+# MESON_FLAGS, e.g. "-Dreadline=enabled"
+
+# examples:
+# 1. build with clang, and the thread-sanitizer
+#   make clean all MESON_FLAGS="-Db_sanitize=thread" CXX=clang++ CC=clang
+
 all: $(BUILDDIR)
 	$(NINJA) -C $(BUILDDIR)
 
 $(BUILDDIR):
-	$(MESON) $(BUILDDIR)
+	$(MESON) $(MESON_FLAGS) $(BUILDDIR)
 
 check: test
 
@@ -34,6 +41,10 @@ test: $(BUILDDIR)
 test-valgrind: $(BUILDDIR)
 	@cd $(BUILDDIR); $(MESON) test --wrap='valgrind --leak-check=full --error-exitcode=1'
 
+test-helgrind: $(BUILDDIR)
+	@cd $(BUILDDIR); $(MESON) test --wrap='valgrind --tool=helgrind --error-exitcode=1'
+
+
 dist: $(BUILDDIR)
 	@cd $(BUILDDIR); $(MESON) dist