@jonasschnelli wrote in #14979:
> #14573 broke < Qt5.6 compatibility due to calling the lambda version of `addAction` that was added in Qt5.6.

We currently [support](https://github.com/bitcoin/bitcoin/blob/master/doc/dependencies.md) QT >=5.2, but hardly anyone tests with that. If we make one of the Travis machines use it, we should have a better change of catching this.

See also discussion about minimum QT version in #13478 
{
    std::shared_ptr<CReserveKey> rKey = std::make_shared<CReserveKey>(this);
    CPubKey pubkey;
    if (!rKey->GetReservedKey(pubkey))
        return;
    script = rKey;
    script->reserveScript = CScript() << ToByteVector(pubkey) << OP_CHECKSIG;
}
void CWallet::LockCoin(const COutPoint& output)
{
    AssertLockHeld(cs_wallet); 
    setLockedCoins.insert(output);
}
void CWallet::UnlockCoin(const COutPoint& output)
{
    AssertLockHeld(cs_wallet); 
    setLockedCoins.erase(output);
}
void CWallet::UnlockAllCoins()
{
    AssertLockHeld(cs_wallet); 
    setLockedCoins.clear();
}
bool CWallet::IsLockedCoin(uint256 hash, unsigned int n) const
{
    AssertLockHeld(cs_wallet); 
    COutPoint outpt(hash, n);
    return (setLockedCoins.count(outpt) > 0);
}
void CWallet::ListLockedCoins(std::vector<COutPoint>& vOutpts) const