nightly build error

[<don...@is...>]

  ...
 ;; Loaded file /root/clisp/build-dir/trace.fas
 ;; Loading file /root/clisp/build-dir/cmacros.fas ...
 ;; Loaded file /root/clisp/build-dir/cmacros.fas
 ;; Loading file /root/clisp/build-dir/compiler.fas ...
 *** - SYSTEM::%FIND-PACKAGE: There is no package with name "COMPILER"
 Bye.
 make: *** [interpreted.mem] Error 1

make clean solves the problem
But this is not a minor inconvenience when you're doing 5 nightly
builds.  I think I've tried to raise this problem before.
Are there cases where you (developers) care about causing incremental
make's to break?  Or should I just start my nightly builds with make clean?