- What I did

Ensure that make raises an error if mktemp, for whatever reason, returns an empty string. This could possibly happen if, for some reason, the /tmp directory was chown'd or there was no free space left on the system.

This pull request makes sure that it won't rm -rf /* the system out of existence in case $@_TMP_OUT is an empty string.

If $($@_TMP_OUT) was empty,

rm -rf "$($@_TMP_OUT)"/*

would evaluate to

rm -rf /*

What would happen next is up to your imagination

- How I did it

I did it by adding

ifeq ($($@_TMP_OUT),)
    $(error Could not create temp directory.)
endif

after

$(eval $@_TMP_OUT := $(shell mktemp -d -t moby-output.XXXXXXXXXX))

in the Makefile

- How to verify it

Run make generate-files

- Description for the changelog

• Fix potential system wipe