diff --git a/src/librustc_asan/build.rs b/src/librustc_asan/build.rs
index cc856ba68fbb7..645707ccc0338 100644
--- a/src/librustc_asan/build.rs
+++ b/src/librustc_asan/build.rs
@@ -4,6 +4,7 @@ use build_helper::sanitizer_lib_boilerplate;
 use cmake::Config;
 
 fn main() {
+    println!("cargo:rerun-if-env-changed=RUSTC_BUILD_SANITIZERS");
     if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
         return;
     }
diff --git a/src/librustc_lsan/build.rs b/src/librustc_lsan/build.rs
index d5f3e37dea51c..73720d8c2d64e 100644
--- a/src/librustc_lsan/build.rs
+++ b/src/librustc_lsan/build.rs
@@ -4,6 +4,7 @@ use build_helper::sanitizer_lib_boilerplate;
 use cmake::Config;
 
 fn main() {
+    println!("cargo:rerun-if-env-changed=RUSTC_BUILD_SANITIZERS");
     if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
         return;
     }
diff --git a/src/librustc_msan/build.rs b/src/librustc_msan/build.rs
index de1676f489a46..a81786ee36d04 100644
--- a/src/librustc_msan/build.rs
+++ b/src/librustc_msan/build.rs
@@ -4,6 +4,7 @@ use build_helper::sanitizer_lib_boilerplate;
 use cmake::Config;
 
 fn main() {
+    println!("cargo:rerun-if-env-changed=RUSTC_BUILD_SANITIZERS");
     if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
         return;
     }
diff --git a/src/librustc_tsan/build.rs b/src/librustc_tsan/build.rs
index 6df9691257455..f9333e1502327 100644
--- a/src/librustc_tsan/build.rs
+++ b/src/librustc_tsan/build.rs
@@ -4,6 +4,7 @@ use build_helper::sanitizer_lib_boilerplate;
 use cmake::Config;
 
 fn main() {
+    println!("cargo:rerun-if-env-changed=RUSTC_BUILD_SANITIZERS");
     if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
         return;
     }