Improve offset calculation in wide int builds

* src/alloc.c (mark_maybe_object): Make sure that OFFSET isn’t widened
during subtraction.
1 job for master in 72 minutes and 57 seconds (queued for 3 seconds)
Status Job ID Name Coverage
failed #6790


Name Stage Failure
test-all Test
make[2]: *** [check-doit] Error 1
Makefile:318: recipe for target 'check-doit' failed
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:293: recipe for target 'check-expensive' failed
make[1]: *** [check-expensive] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
Makefile:959: recipe for target 'check-expensive' failed
make: *** [check-expensive] Error 2
ERROR: Job failed: exit code 1