diff --git a/.gitmodules b/.gitmodules
index 72c078326f..13774cbbfd 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -70,3 +70,6 @@
 [submodule "auxil/zeek-af_packet-plugin"]
 	path = auxil/zeek-af_packet-plugin
 	url = https://github.com/zeek/zeek-af_packet-plugin.git
+[submodule "auxil/libunistd"]
+	path = auxil/libunistd
+	url = https://github.com/zeek/libunistd
diff --git a/auxil/libunistd b/auxil/libunistd
new file mode 160000
index 0000000000..cc7ac8d20a
--- /dev/null
+++ b/auxil/libunistd
@@ -0,0 +1 @@
+Subproject commit cc7ac8d20a28905be963ae8f5684e793e198892a