diff --git a/kokoro/macos-clang-debug/build.sh b/kokoro/macos-clang-debug/build.sh
index b345eff3c..ba4520164 100644
--- a/kokoro/macos-clang-debug/build.sh
+++ b/kokoro/macos-clang-debug/build.sh
@@ -17,4 +17,4 @@ set -e  # fail on error
 set -x  # display commands
 
 SCRIPT_DIR=`dirname "$BASH_SOURCE"`
-source $SCRIPT_DIR/../scripts/macos/build.sh DEBUG clang
+source $SCRIPT_DIR/../scripts/macos/build.sh DEBUG clang -DAMBER_ENABLE_SWIFTSHADER=TRUE