gdal: fix arrow variant for 32-bit

[barracuda156]

Description

No revbump needed here. It would simply not build with this variant otherwise.

Type(s)

• bugfix
• enhancement
• security fix

Tested on

macOS 10.6
Xcode 3.2

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 --nitpick?
• 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?

[macportsbot]

Notifying maintainers:
@nilason for port gdal.
@Veence for port gdal.

[nilason]

I can’t test this, I trust you on this.

[barracuda156]

I can’t test this, I trust you on this.

Yes, I have built it successfully after adding the fix, of course.

[Dave-Allured]

@barracuda156 for expediency I merged your arrow 32 bit changes into my new update PR #24695. Okay with you? Please review that new PR.

[barracuda156]

Closing in favor of #24695