py-pytorch: Update to version 2.9.1

[essandess]

Note: I am unable to compile this locally because of MetalToolchain issues. However, this has been apparently fixed for the buildbots [?], so I will try to see if this builds here.

Please also see:

• https://trac.macports.org/wiki/TahoeProblems#MetaltoolchainisnolongerbundledinXcode
• https://trac.macports.org/ticket/73262
• https://lists.macports.org/pipermail/macports-dev/2025-November/046556.html

Description

Type(s)

• bugfix
• enhancement
• security fix

Tested on

macOS x.y
Xcode x.y / Command Line Tools x.y.z

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?

[essandess]

Note: I removed parallel builds because of build failures on a box with these versions. I wasn't able to track down the cause of the build error, as there were no log errors.

macOS 15.7.2 24G325 arm64
Xcode 26.1.1 17B100

[essandess]

I confirm that this builds on arm64 and x86_64.