diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..b4aec63
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,41 @@
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::iter;
+use std::path::Path;
+
+/*
+#[doc(hidden)]
+#[macro_export]
+macro_rules! count {
+    () => { proc_macro_call_0!() };
+    (!) => { proc_macro_call_1!() };
+    (!!) => { proc_macro_call_2!() };
+    ...
+}
+*/
+
+fn main() {
+    let out_dir = env::var("OUT_DIR").unwrap();
+    let dest_path = Path::new(&out_dir).join("count.rs");
+    let mut f = File::create(&dest_path).unwrap();
+
+    let mut content = String::new();
+    content += "
+        #[doc(hidden)]
+        #[macro_export]
+        macro_rules! count {
+    ";
+    for i in 0..=64 {
+        let bangs = iter::repeat("!").take(i).collect::<String>();
+        content += &format!("({}) => {{ proc_macro_call_{}!() }};", bangs, i);
+    }
+    content += "
+            ($(!)+) => {
+                compile_error!(\"this macro does not support >64 nested macro invocations\")
+            };
+        }
+    ";
+
+    f.write_all(content.as_bytes()).unwrap();
+}