Compilation lint error re. use of rassq-delete-all

[purcell]

Hey @tarsius, I see that the build fails for emacs HEAD due to the following new compilation error:

Compiling package-build.el

In toplevel form:
package-build.el:1219:31: Error: value from call to ‘assq-delete-all’ is unused
make: *** [Makefile:32: package-build.elc] Error 1

I wasn't sure if the correct fix was just to assign the result back to the let-bound var locally, or if it indicates an issue with the logic. Any idea?

[tarsius]

Mostly harmless; but we are dealing with a wacky api and encoding issues, so its worth a few comments.

[purcell]

Nice, makes sense, thanks!