diff --git a/btls-sys/build/main.rs b/btls-sys/build/main.rs
index 8d1d9a26..184e5b00 100644
--- a/btls-sys/build/main.rs
+++ b/btls-sys/build/main.rs
@@ -658,6 +658,7 @@ fn main() -> ExitCode {
 
 fn run() -> Result<(), Box<dyn std::error::Error>> {
     let config = Config::from_env()?;
+    emit_rerun_if_changed();
     ensure_patches_applied(&config)?;
     if !config.env.docs_rs {
         emit_link_directives(&config);
@@ -688,6 +689,10 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
     Ok(())
 }
 
+fn emit_rerun_if_changed() {
+    println!("cargo:rerun-if-changed=patches");
+}
+
 fn emit_link_directives(config: &Config) {
     let bssl_dir = build_boringssl_or_get_prebuilt(config);
     let msvc_lib_subdir = msvc_lib_subdir(config);