bug#49495: 27.2; portable dumper incompatible with 64K pages on aarch64

["Dan Čermák" <dan.cermak@cgc-instruments.com>]

I am forwarding a bugreport from Fedora, about the portable dumper
causing issues when launching Emacs in a RHEL 8 chroot on aarch64:
(from https://bugzilla.redhat.com/show_bug.cgi?id=1974244)

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The emacs binary from emacs-nox-27.2-2.fc33.aarch64 cannot start in a chroot on Red Hat Enterprise Linux 8 because it assumes 4K pages:

openat(AT_FDCWD, "/usr/bin/emacs-27.2-nox.pdmp", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=10124128, ...}) = 0
read(3, "DUMPEDGNUEMACS\0\0(\304wp;D\330G%\f\265\337\214\264VO"..., 80) = 80
mmap(NULL, 10124128, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xffff92240000
mmap(0xffff92240000, 6946816, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0xffff92240000
mmap(0xffff928e0000, 90112, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x6a0000) = 0xffff928e0000
mmap(0xffff928f6000, 3087200, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x6b6000) = -1 EINVAL (Invalid argument)

Map offsets and addresses must be a multiple of the page size.
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Unfortunately, I am not really familiar with Emacs' internals to know
how to handle this bug report.

Cheers,

Dan