diff --git a/build.rs b/build.rs
index d515e86..7e95e6b 100644
--- a/build.rs
+++ b/build.rs
@@ -121,7 +121,7 @@ fn compile_probe(rustc_bootstrap: bool) -> bool {
         .arg("--edition=2018")
         .arg("--crate-name=anyhow")
         .arg("--crate-type=lib")
-        .arg("--emit=metadata")
+        .arg("--emit=dep-info,metadata")
         .arg("--out-dir")
         .arg(out_dir)
         .arg(probefile);
diff --git a/build/probe.rs b/build/probe.rs
index 1dfc244..21e776d 100644
--- a/build/probe.rs
+++ b/build/probe.rs
@@ -30,3 +30,6 @@ impl Error for MyError {
 }
 
 const _: fn(&dyn Error) -> Option<&Backtrace> = |err| error::request_ref::<Backtrace>(err);
+
+// Include in sccache cache key.
+const _: Option<&str> = option_env!("RUSTC_BOOTSTRAP");