On Tue, Aug 11, 2020 at 2:52 PM Eli Zaretskii <eliz@gnu.org> wrote:
>   pdumper.c: In function 'hash_table_thaw':
>   pdumper.c:2667:30: error: conversion from 'EMACS_INT' {aka 'long long int'} to 'ptrdiff_t' {aka 'int'} may change value [-Werror=conversion]
>    2667 |   h->hash = make_nil_vector (XFIXNUM (h->hash));
>         |                              ^~~~~~~~~~~~~~~~~
>   cc1.exe: some warnings being treated as errors

I suggest going back to Fmake_vector (h->hash, Qnil), as in the
attached patch. It's shorter, and it actually compiles.