don't emit rerun-if-changed unless the path exists and is readable

Author: reaperhulk

openssl-sys/build/main.rs

@@ -84,7 +84,9 @@ fn main() {
     // every time when vendoring so we disable it.
     #[cfg(not(feature = "vendored"))]
     if let Some(printable_include) = include_dir.join("openssl").to_str() {
-        println!("cargo:rerun-if-changed={}", printable_include);
+        if include_dir.join("openssl").exists() {
+            println!("cargo:rerun-if-changed={}", printable_include);
+        }
     }
 
     if !lib_dirs.iter().all(|p| p.exists()) {