diff --git a/build/envsetup.sh b/build/envsetup.sh
index 03c83e30..bc96600f 100644
--- a/build/envsetup.sh
+++ b/build/envsetup.sh
@@ -942,3 +942,8 @@ function fixup_common_out_dir() {
         mkdir -p ${common_out_dir}
     fi
 }
+
+# Enable ThinLTO Source wide.
+echo "Building with ThinLTO."
+export GLOBAL_THINLTO=true
+export USE_THINLTO_CACHE=true