weird build error in my environment

[joakim]

This probably only affects me in my environment, but I've never seen
this type of error and I'm curious: what could I have done to cause this?

bzr pull
make clean bootstrap
...........
Wrote /mnt/data/build/emacs-branches/emacs/branches/winprop/lisp/xt-mouse.elc
make[3]: Leaving directory 
`/mnt/data/build/emacs-branches/emacs/branches/winprop/lisp'
make -w compile-last
make[3]: Entering directory 
`/mnt/data/build/emacs-branches/emacs/branches/winprop/lisp'

Error in KERNEL::UNBOUND-SYMBOL-ERROR-HANDLER:  the variable L is unbound.
   [Condition of type UNBOUND-VARIABLE]

Restarts:
  0: [ABORT] Return to Top-Level.

Debug  (type H for help)

(EVAL L)
Source: Error finding source: 
Error in function DEBUG::GET-FILE-TOP-LEVEL-FORM:  Source file no longer exists:
  target:code/eval.lisp.
0] 
-- 
Joakim Verona