aufs-util: use $(HOST_MAKE_ENV) when calling $(MAKE)

In this case in particular a host tool is built inside the target build
step.

Signed-off-by: Gustavo Zacarias <gustavo.zacarias@free-electrons.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/aufs-util/aufs-util.mk

@@ -41,7 +41,7 @@ AUFS_UTIL_POST_PATCH_HOOKS += AUFS_UTIL_REMOVE_RDU64
 
 # First, we build the host tools, needed to build the target tools.
 define AUFS_UTIL_BUILD_CMDS
-	$(MAKE) -C $(@D) \
+	$(HOST_MAKE_ENV) $(MAKE) -C $(@D) \
 		$(HOST_CONFIGURE_OPTS) \
 		CPPFLAGS="$(AUFS_UTIL_HOST_CPPFLAGS)" \
 		HOSTCC="$(HOSTCC)" HOSTLD="$(HOSTLD)" \