WIP meta pool contracts with gauge token support

contracts/interfaces/IGauge.sol

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+// SPDX-License-Identifier: MIT
+
+pragma solidity >=0.5.0;
+
+/// @title IGauge interface
+/// @notice This interface can be used for any contracts that has
+/// gauge like functionalities.
+interface IGauge {
+    function deposit(uint256) external;
+
+    function withdraw(uint256) external;
+
+    function lp_token() external view returns (address);
+
+    function set_rewards_receiver(address) external;
+
+    // Below are ChildGauge specific methods. Using them for
+    // other contracts will result in revert.
+
+    function SDL() external view returns (address);
+
+    function FACTORY() external view returns (address);
+}

contracts/interfaces/IMinterLike.sol

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+// SPDX-License-Identifier: MIT
+
+pragma solidity >=0.5.0;
+
+/// @title IMinterLike interface
+/// @notice This interface can be used for any contracts that has
+/// minter like functionalities. For example ChildGaugeFactory
+/// on a side chain is a minter like contract.
+interface IMinterLike {
+    function mint(address gauge) external;
+}