Do any of the Linux interfaces support bughouse/crazyhouse?
XBoard supports about anything under the Sun:
Chess, Chess960, Xiangqi, Shogi, Makruk, Suicide/Giveaway, Losers, Crazyhouse, 3Check, Twokings, Atomic, Cylinder, Shatranj, Courier, Capablanca/Gothic/CRC, Seirawan, Janus, Falcon, Spartan, Berolina, Knightmate, Superchess, Grand Chess, Great Shatranj, Mighty Lion, Elven Chess, Chu Shogi. And as if that is not enough engines can now define their own variants and configure XBoard to know the rules. E.g. with the fairymax engine it also does King of the Hill, Charge of the Light Brigade, Bifurcator Chess, Team-Mate Chess, Ouk and Ai-Wok. And many flavors of Chess with different Armies (all playable as variant 'fairy' with an engine option to select the setup for that).
Bughouse is a 4-player game, and can only be played through an Internet Chess Server to connect two XBoards (as XBoard is a two-player interface). XBoard has an extra board window to show the partner game, though.
Crazyhouse
Spartan Chess
Do any of the Linux interfaces support bughouse/crazyhouse?