qt64: Re-enable for 10.14

[tuffnatty]

Description

Now that #25514 has been merged, most qt64 packages build successfully on 10.14, but alas! 3ddc4db has just shifted the minimal supported version to 10.15. This patch reverts the qt64 part of that commit.

Type(s)

• bugfix
• enhancement
• security fix

Tested on

macOS 10.14.6 18G9323 x86_64
Xcode 11.3.1 11C505

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?

[macportsbot]

Notifying maintainers:
@MarcusCalhoun-Lopez for port qt64.

[reneeotten]

@tuffnatty Upstream does not support it. If you can show that all subports of the qt64 port successfully build on 10.14; then sure, we can re-enable it.

[tuffnatty]

@reneeotten https://doc.qt.io/archives/qt-6.4/supported-platforms.html : macOS 10.14 is supported. Xcode 11 is not supported, right, but somehow it did not matter before 20.12.2024, and we're already using mp-clang instead of Xcode in many other places.
I can try to rebuild all the packages here. AFAIR, only qtwebkit had to be patched, and people here are not very eager to maintain qtwebkit/chromium patches.

[reneeotten]

Yes, it is supported as a target platform but not as a build platform since Xcode 13 or 14 is required.
I am okay with merging this but please add a comment that 10.14 is not officially supported upstream.