diff --git a/mk/config.mk b/mk/config.mk
index cdd69bd..3c28853 100644
--- a/mk/config.mk
+++ b/mk/config.mk
@@ -23,7 +23,7 @@ CONTAINERFILE?=podman/redox-base-containerfile
 # Per host variables
 # TODO: get host arch automatically
 HOST_ARCH=x86_64
-HOST_CARGO=env --unset=RUSTUP_TOOLCHAIN cargo
+HOST_CARGO=env -u RUSTUP_TOOLCHAIN cargo
 UNAME := $(shell uname)
 ifeq ($(UNAME),Darwin)
 	FUMOUNT=sudo umount