message: Remove C++17 toolchain hack.
  Android and iOS correctly pass `-std=c++17` in UE5.
diff: @@ -198,28 +198,5 @@ public class CesiumRuntime : ModuleRules
  PrivatePCHHeaderFile = "Private/PCH.h";
  CppStandard = CppStandardVersion.Cpp17;
  bEnableExceptions = true;
  -
  - if (Target.Platform == UnrealTargetPlatform.IOS ||
  - (Target.Platform == UnrealTargetPlatform.Android &&
  - Target.Version.MajorVersion == 4 &&
  - Target.Version.MinorVersion == 26 &&
  - Target.Version.PatchVersion < 2))
  - {
  - // In UE versions prior to 4.26.2, the Unreal Build Tool on Android
  - // (AndroidToolChain.cs) ignores the CppStandard property and just
  - // always uses C++14. Our plugin can't be compiled with C++14.
  - //
  - // So this hack uses reflection to add an additional argument to
  - // the compiler command-line to force C++17 mode. Clang ignores all
  - // but the last `-std=` argument, so the `-std=c++14` added by the
  - // UBT is ignored.
  - //
  - // This is also needed for iOS builds on all engine versions as Unreal
  - // defaults to c++14 regardless of the CppStandard setting
  - Type type = Target.GetType();
  - FieldInfo innerField = type.GetField("Inner", BindingFlags.Instance | BindingFlags.NonPublic);
  - TargetRules inner = (TargetRules)innerField.GetValue(Target);
  - inner.AdditionalCompilerArguments += " -std=c++17";
  - }
  }
  }
  