diff --git a/util/cxx_config/Makefile b/util/cxx_config/Makefile
index 455d0317b1..fa6ea5b81f 100644
--- a/util/cxx_config/Makefile
+++ b/util/cxx_config/Makefile
@@ -33,7 +33,7 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-ARCH = ARM
+ARCH ?= ARM
 VARIANT = opt
 
 CXXFLAGS = -I../../build/$(ARCH) -L../../build/$(ARCH) -DTRACING_ON=1