r7829-42dc0e2594 is failing to compile due to base-files.
I initially thought it could be due to my configuration, so I started a brand new .config with minimal options, and it still fails due to the same package.
I used that patch once to create the new ucert build keys, and noticed that after that you do not even need the patch, if you just copy the new keys all your possible buildroots (I have 3 parallel master buildroots).
Alternatively, you can apparently also disable packages list signing, but I have not tried that.