Hi.
If you try to

Json::Value someJsonValue;
int64_t someIntValue = 45;  // <-- note on type
someJsonValue = someIntValue;  // <-- error

you'll get a compiler error error: conversion from 'int64_t' (aka 'long') to 'Json::Value' is ambiguous.
On iOS it compiles fine both for armv7 and arm64, but on android arm64-v8a long and long long are different enough to trigger compiler error, however both are 8 bytes.