diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index 9d57a4f00d7..9a964457ef2 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -212,6 +212,7 @@ pub fn std_cargo(builder: &Builder<'_>,
                 emscripten: false,
             });
             cargo.env("LLVM_CONFIG", llvm_config);
+            cargo.env("RUSTC_BUILD_SANITIZERS", "1");
         }
 
         cargo.arg("--features").arg(features)
diff --git a/src/librustc_asan/build.rs b/src/librustc_asan/build.rs
index a2b4b090efb..cc856ba68fb 100644
--- a/src/librustc_asan/build.rs
+++ b/src/librustc_asan/build.rs
@@ -4,6 +4,9 @@
 use cmake::Config;
 
 fn main() {
+    if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
+        return;
+    }
     if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
         build_helper::restore_library_path();
 
diff --git a/src/librustc_lsan/build.rs b/src/librustc_lsan/build.rs
index b8c7b7c2d55..d5f3e37dea5 100644
--- a/src/librustc_lsan/build.rs
+++ b/src/librustc_lsan/build.rs
@@ -4,6 +4,9 @@
 use cmake::Config;
 
 fn main() {
+    if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
+        return;
+    }
     if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
         build_helper::restore_library_path();
 
diff --git a/src/librustc_msan/build.rs b/src/librustc_msan/build.rs
index 1c66b0a9cd3..de1676f489a 100644
--- a/src/librustc_msan/build.rs
+++ b/src/librustc_msan/build.rs
@@ -4,6 +4,9 @@
 use cmake::Config;
 
 fn main() {
+    if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
+        return;
+    }
     if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
         build_helper::restore_library_path();
 
diff --git a/src/librustc_tsan/build.rs b/src/librustc_tsan/build.rs
index ed9c37087c7..6df96912574 100644
--- a/src/librustc_tsan/build.rs
+++ b/src/librustc_tsan/build.rs
@@ -4,6 +4,9 @@
 use cmake::Config;
 
 fn main() {
+    if env::var("RUSTC_BUILD_SANITIZERS") != Ok("1".to_string()) {
+        return;
+    }
     if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
         build_helper::restore_library_path();