Compilation of contracts failing

[fabifrank]

,EfficientAirdrop/contracts/zeppelin/ownership/Ownable.sol:24:3: Warning: Defining constructors as functions with the same name as the contract is deprecated. Use "constructor(...) { ... }" instead.
  function Ownable() public {
  ^ (Relevant source part starts here and spans across multiple lines).
,contracts/zeppelin/ERC20/BasicToken.sol:36:5: Warning: Invoking events without "emit" prefix is deprecated.
    Transfer(msg.sender, _to, _value);
    ^-------------------------------^
,contracts/zeppelin/ERC20/StandardToken.sol:40:5: Warning: Invoking events without "emit" prefix is deprecated.
    Transfer(_from, _to, _value);
    ^--------------------------^
,contracts/zeppelin/ERC20/StandardToken.sol:55:5: Warning: Invoking events without "emit" prefix is deprecated.
    Approval(msg.sender, _spender, _value);
    ^------------------------------------^
,contracts/zeppelin/ERC20/StandardToken.sol:94:5: Warning: Invoking events without "emit" prefix is deprecated.
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    ^-----------------------------------------------------------^
,contracts/zeppelin/ERC20/StandardToken.sol:120:5: Warning: Invoking events without "emit" prefix is deprecated.
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    ^-----------------------------------------------------------^
,contracts/zeppelin/ownership/Ownable.sol:43:5: Warning: Invoking events without "emit" prefix is deprecated.
    OwnershipRenounced(owner);
    ^-----------------------^
,contracts/zeppelin/ownership/Ownable.sol:61:5: Warning: Invoking events without "emit" prefix is deprecated.
    OwnershipTransferred(owner, _newOwner);
    ^------------------------------------^
,contracts/zeppelin/ERC20/MintableToken.sol:46:5: Warning: Invoking events without "emit" prefix is deprecated.
    Mint(_to, _amount);
    ^----------------^
,contracts/zeppelin/ERC20/MintableToken.sol:47:5: Warning: Invoking events without "emit" prefix is deprecated.
    Transfer(address(0), _to, _amount);
    ^--------------------------------^
,contracts/zeppelin/ERC20/MintableToken.sol:57:5: Warning: Invoking events without "emit" prefix is deprecated.
    MintFinished();
    ^------------^
,contracts/utils/MerkleUtils.sol:37:24: Warning: This function only accepts a single "bytes" argument. Please use "abi.encodePacked(...)" or a similar function to encode the data.
        return bytes32(keccak256(fullLeaf));
                       ^-----------------^
,contracts/utils/MerkleUtils.sol:37:24: Warning: The provided argument of type string memory is not implicitly convertible to expected type bytes memory.
        return bytes32(keccak256(fullLeaf));
                       ^-----------------^
,contracts/utils/MerkleUtils.sol:50:21: Warning: This function only accepts a single "bytes" argument. Please use "abi.encodePacked(...)" or a similar function to encode the data.
                h = keccak256(h, el);
                    ^--------------^
,contracts/utils/MerkleUtils.sol:52:21: Warning: This function only accepts a single "bytes" argument. Please use "abi.encodePacked(...)" or a similar function to encode the data.
                h = keccak256(el, h);
                    ^--------------^
,EfficientAirdrop/contracts/EfficientAirdrop.sol:52:13: Warning: Invoking events without "emit" prefix is deprecated.
            AirdropTransfer(_who, _amount);
            ^----------------------------^
,EfficientAirdrop/contracts/utils/MerkleUtils.sol:37:24: Warning: This function only accepts a single "bytes" argument. Please use "abi.encodePacked(...)" or a similar function to encode the data.
        return bytes32(keccak256(fullLeaf));
                       ^-----------------^
,EfficientAirdrop/contracts/utils/MerkleUtils.sol:37:24: Warning: The provided argument of type string memory is not implicitly convertible to expected type bytes memory.
        return bytes32(keccak256(fullLeaf));
                       ^-----------------^
,EfficientAirdrop/contracts/utils/MerkleUtils.sol:50:21: Warning: This function only accepts a single "bytes" argument. Please use "abi.encodePacked(...)" or a similar function to encode the data.
                h = keccak256(h, el);
                    ^--------------^
,EfficientAirdrop/contracts/utils/MerkleUtils.sol:52:21: Warning: This function only accepts a single "bytes" argument. Please use "abi.encodePacked(...)" or a similar function to encode the data.
                h = keccak256(el, h);
                    ^--------------^
,EfficientAirdrop/contracts/zeppelin/ERC20/BasicToken.sol:36:5: Warning: Invoking events without "emit" prefix is deprecated.
    Transfer(msg.sender, _to, _value);
    ^-------------------------------^
,EfficientAirdrop/contracts/zeppelin/ERC20/MintableToken.sol:46:5: Warning: Invoking events without "emit" prefix is deprecated.
    Mint(_to, _amount);
    ^----------------^
,EfficientAirdrop/contracts/zeppelin/ERC20/MintableToken.sol:47:5: Warning: Invoking events without "emit" prefix is deprecated.
    Transfer(address(0), _to, _amount);
    ^--------------------------------^
,EfficientAirdrop/contracts/zeppelin/ERC20/MintableToken.sol:57:5: Warning: Invoking events without "emit" prefix is deprecated.
    MintFinished();
    ^------------^
,EfficientAirdrop/contracts/zeppelin/ERC20/StandardToken.sol:40:5: Warning: Invoking events without "emit" prefix is deprecated.
    Transfer(_from, _to, _value);
    ^--------------------------^
,EfficientAirdrop/contracts/zeppelin/ERC20/StandardToken.sol:55:5: Warning: Invoking events without "emit" prefix is deprecated.
    Approval(msg.sender, _spender, _value);
    ^------------------------------------^
,EfficientAirdrop/contracts/zeppelin/ERC20/StandardToken.sol:94:5: Warning: Invoking events without "emit" prefix is deprecated.
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    ^-----------------------------------------------------------^
,EfficientAirdrop/contracts/zeppelin/ERC20/StandardToken.sol:120:5: Warning: Invoking events without "emit" prefix is deprecated.
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    ^-----------------------------------------------------------^
,EfficientAirdrop/contracts/zeppelin/ownership/Ownable.sol:43:5: Warning: Invoking events without "emit" prefix is deprecated.
    OwnershipRenounced(owner);
    ^-----------------------^
,EfficientAirdrop/contracts/zeppelin/ownership/Ownable.sol:61:5: Warning: Invoking events without "emit" prefix is deprecated.
    OwnershipTransferred(owner, _newOwner);
    ^------------------------------------^
Compilation failed. See above.

[fabifrank]

Which truffle are you using @stefanionescu ?
I am currently using v4.1.14.

[fabifrank]

Could you also paste the solidity compiler version you're using?

./node_modules/solc/solcjs --version

[stefanionescu]

Also using 4.1.14. My solidity compiler is 0.4.24