fix: Trigger rebuild on changes

build.rs

@@ -1,18 +1,36 @@
 use std::path::PathBuf;
 
 fn main() {
-    let datasketches = PathBuf::from("datasketches-cpp");
-    let src = PathBuf::from("src");
-    let mut bridge = cxx_build::bridge(src.join("bridge.rs"));
+    let datasketches_src = PathBuf::from("datasketches-cpp");
+    let rust_src = PathBuf::from("src");
+
+    let mut bridge = cxx_build::bridge(rust_src.join("bridge.rs"));
+
+    println!(
+        "cargo:rerun-if-changed={}",
+        rust_src.join("bridge.rs").to_str().unwrap()
+    );
+    println!(
+        "cargo:rerun-if-changed={}",
+        datasketches_src.join("cpc.cpp").to_str().unwrap()
+    );
+    println!(
+        "cargo:rerun-if-changed={}",
+        datasketches_src.join("theta.cp").to_str().unwrap()
+    );
+    println!(
+        "cargo:rerun-if-changed={}",
+        datasketches_src.join("hh.cpp").to_str().unwrap()
+    );
 
     assert!(bridge.is_flag_supported("-std=c++11").expect("supported"));
     bridge
         .files(&[
-            datasketches.join("cpc.cpp"),
-            datasketches.join("theta.cpp"),
-            datasketches.join("hh.cpp"),
+            datasketches_src.join("cpc.cpp"),
+            datasketches_src.join("theta.cpp"),
+            datasketches_src.join("hh.cpp"),
         ])
-        .include(datasketches.join("common").join("include"))
+        .include(datasketches_src.join("common").join("include"))
         .flag_if_supported("-std=c++11")
         .cpp_link_stdlib("stdc++")
         .static_flag(true)