fix(ios): force fmt to c++17 for Xcode 26

[samholmes]

Newer Apple Clang toolchains fail to compile fmt 11.0.2 under C++20 with consteval-related errors, blocking simulator builds on Xcode 26.

Keep the workaround in Podfile post_install so pod regeneration consistently reapplies FMT_USE_CONSTEVAL=0 and fmt-specific C++17 settings instead of requiring manual edits in Pods/.

CHANGELOG

Does this branch warrant an entry to the CHANGELOG?

• Yes
• No

Dependencies

none

Requirements

If you have made any visual changes to the GUI. Make sure you have:

• Tested on iOS device
• Tested on Android device
• Tested on small-screen device (iPod Touch)
• Tested on large-screen device (tablet)

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Note

Medium Risk
Moderate risk because it changes global pod build settings and post-install behavior, which can affect compilation flags across dependencies and may introduce subtle build issues on other Xcode/CI configurations.

Overview
Fixes Xcode/Apple Clang build failures by adding Podfile post_install workarounds for the fmt pod: globally defines FMT_USE_CONSTEVAL=0 and forces fmt to compile as C++17.

Because react_native_post_install can override podspec C++ settings, the PR also re-applies the fmt C++17 settings after that step (including updating generated .xcconfig files) so the workaround persists across pod install regenerations.

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

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First C++17 setting for fmt is dead code

Low Severity

The CLANG_CXX_LANGUAGE_STANDARD = 'c++17' setting for fmt at lines 82–84 is overwritten by react_native_post_install (line 109), which the comment at line 116 explicitly acknowledges resets C++ standards. Only the second block (lines 119–139) has a lasting effect, making the first setting dead code that could mislead future maintainers into thinking it's effective.

Additional Locations (1)

• ios/Podfile#L118-L139

 

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