How to debug problems during temacs?

[Simon Josefsson]

I have made some C level changes to my Emacs, which worked fine up
until I did cvs update a few days ago.  How would I debug a error like
the below?  "debug.el" doesn't seem available in temacs, so toggling
debug-on-error doesn't work.  Using gdb to find the cause for this
lisp error is beyond me right now.

(I'm assuming that the error below is due to my changes, so what I'm
asking for is hints on how to debug it, not that anyone should spend
time solving this bug.  I have done a make distclean + configure +
make but the error persists. I have not modified any lisp code, FWIW.)

LC_ALL=C ./temacs -batch -l loadup dump
Loading loadup (source)...
Using load-path (/home/jas/src/emacs/lisp)
Loading byte-run...
Loading subr (compiled; note, source file is newer)...
Loading version.el (source)...
Loading widget...
Loading custom (compiled; note, source file is newer)...
Loading emacs-lisp/backquote...
Loading map-ynp...
Loading env (compiled; note, source file is newer)...
Loading cus-start (source)...
Note, built-in variable `recursive-load-depth-limit' not bound
Loading international/mule (compiled; note, source file is newer)...
Loading international/mule-conf.el (source)...
Loading format...
Loading bindings (compiled; note, source file is newer)...
Loading simple (compiled; note, source file is newer)...
Loading files (compiled; note, source file is newer)...
Loading faces (compiled; note, source file is newer)...
Lists of integers (garbage collection statistics) are normal output
while building Emacs; they do not indicate a problem.
((8001 . 8100) (4009 . 0) (488 . 0) 13314 21981 (3 . 3) (16 . 0) (755 . 2206))
Loading loaddefs.el (source)...
((19326 . 14557) (5946 . 0) (498 . 7) 30791 21981 (5 . 1) (16 . 0) (2656 . 
2069))
Loading help...
Loading international/mule-cmds (compiled; note, source file is newer)...
Loading case-table...
Loading international/characters (compiled; note, source file is newer)...
Wrong type argument: arrayp, nil
make[1]: *** [emacs] Error 255
make[1]: Leaving directory `/home/jas/src/emacs/src'
make: *** [src] Error 2