Compile failure with latest cesium-native on Unreal/Android due to <numbers>

[kring]

In file included from D:/a/cesium-unreal/cesium-unreal/extern/cesium-native/CesiumGeometry/src/IntersectionTests.cpp:7:
D:/a/cesium-unreal/cesium-unreal/extern/cesium-native/CesiumUtility/include/CesiumUtility/Math.h:7:10: fatal error: 'numbers' file not found

#include <numbers>

         ^~~~~~~~~

1 error generated.

This header file was introduced to libc++ with Clang 11. See P0631R8 on this page:
https://libcxx.llvm.org/Status/Cxx20.html

With Unreal 5.3-5.5, we build with NDK r25b, which should be LLVM 14 or so. Yet it's missing the <numbers> header for mysterious reasons. I wasn't able to find much information about this. The closest I could find is this:
termux/termux-packages#13247

In any case, we need to either revert our use of <numbers> in cesium-native, or find some workaround for Unreal/Android builds.

[kring]

Even after the fix above, it still doesn't compile on Android due to the use of std::ranges in BatchTableToGltfStructuralMetadata.cpp. The NDK issue describing this problem is here:
android/ndk#1530

The good news is it has been largely addressed in NDK r26, but the bad news is even UE 5.5 is still on r25b, so it'll be ages before we're free of this problem.