-# Use $(SUBARCH) here instead of $(ARCH) so that this works for UML.
-# In the UML case, $(SUBARCH) is the name of the underlying
-# architecture, while for all other arches, it is the same as $(ARCH).
+# UML needs a little special treatment here. It wants to use the host
+# toolchain, so needs $(SUBARCH) passed to checkstack.pl. Everyone
+# else wants $(ARCH), including people doing cross-builds, which means
+# that $(SUBARCH) doesn't work here.
+ifeq ($(ARCH), um)
+CHECKSTACK_ARCH := $(SUBARCH)
+else
+CHECKSTACK_ARCH := $(ARCH)
+endif