Kirill is right; tpd doesn't work under the union type. The errors
look like this:
/home/hniksic/work/emacs/xemacs-20-hack/src/alloc.c:4329: wrong type argument to unary
exclamation mark
And indeed:
if (!backtrace[i].obj)
The `obj' element of backtrace structure is a Lisp object, so unary !
won't work under union type. To be compatible with union type, you
probably want to use:
if (LISP_TO_VOID (backtrace[i].obj))
Similar mistakes exist in other places in alloc.c.