openfst: update to 1.8.4

[percontation]

Description

FWIW: I wanted this to be able to install python pynini==2.1.7, which is why I have --enable-grm. It works.

Type(s)

• bugfix
• enhancement
• security fix

Tested on

macOS 15.7.2 24G325 arm64
Xcode 26.1.1 17B100

Verification

Have you

• followed our Commit Message Guidelines?
• squashed and minimized your commits?
• checked that there aren't other open pull requests for the same change?
• referenced existing tickets on Trac with full URL in commit message?
• checked your Portfile with port lint?
• tried existing tests with sudo port test?
• tried a full install with sudo port -vst install?
• tested basic functionality of all binary files?
• checked that the Portfile's most important variants haven't been broken?

[percontation]

Huh. This portfile works for me locally, but the github runner consistently gets 403s trying to download http://www.openfst.org/twiki/pub/FST/FstDownload/openfst-1.8.4.tar.gz

Have they done something weird and blocked github??

I don't know how to proceed. Maybe someone can manually add openfst-1.8.4.tar.gz to https://distfiles.macports.org/openfst ?

[percontation]

(^ just did a pointless rebase in hopes that their server would stop 403ing; no luck, still 403s for github runners but builds fine locally).