diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000000000000000000000000000000000000..161d75950cb1be9f3d82f4d0ddb402683fdf0ac0
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "src/hashmap"]
+	path = src/hashmap
+	url = git@github.com:fdekeers/hashmap.c.git
diff --git a/src/hashmap b/src/hashmap
new file mode 160000
index 0000000000000000000000000000000000000000..d51f1e8c8e928a8098d5a3f260a2811c2118fdf7
--- /dev/null
+++ b/src/hashmap
@@ -0,0 +1 @@
+Subproject commit d51f1e8c8e928a8098d5a3f260a2811c2118fdf7