diff --git a/.gitlab-ci/container/build-directx-headers.sh b/.gitlab-ci/container/build-directx-headers.sh
index 4b89d841776..005b45ced59 100644
--- a/.gitlab-ci/container/build-directx-headers.sh
+++ b/.gitlab-ci/container/build-directx-headers.sh
@@ -5,11 +5,11 @@
 # .gitlab-ci/image-tags.yml tags:
 # DEBIAN_BUILD_TAG
 
-set -ex
+set -uex
 
 git clone https://github.com/microsoft/DirectX-Headers -b v1.614.1 --depth 1
 pushd DirectX-Headers
-meson setup build --backend=ninja --buildtype=release -Dbuild-test=false $EXTRA_MESON_ARGS
+meson setup build --backend=ninja --buildtype=release -Dbuild-test=false ${EXTRA_MESON_ARGS:-}
 meson install -C build
 popd
 rm -rf DirectX-Headers