diff --git a/docs/markdown/snippets/zlib_system_dependency.md b/docs/markdown/snippets/zlib_system_dependency.md
new file mode 100644
index 000000000..5bdabf3a0
--- /dev/null
+++ b/docs/markdown/snippets/zlib_system_dependency.md
@@ -0,0 +1,8 @@
+## Add a system type dependency for zlib
+
+This allows zlib to be detected on macOS and FreeBSD without the use of
+pkg-config or cmake, neither of which are part of the base install on those
+OSes (but zlib is).
+
+A side effect of this change is that `dependency('zlib')` also works with
+cmake instead of requiring `dependency('ZLIB')`.