Feral Interactive announces they are working on a Mac OS X port of XCOM: Enemy Unknown for release this spring. Word is this will include all the content released for the strategy remake so far:

The Mac release of XCOM: Enemy Unknown is the Elite Edition, and contains all previously released add-on content and updates. XCOM: Enemy Unknown – Elite Edition includes the Slingshot and Elite Soldier Pack add-on content, as well as the Second Wave update, which includes a series of gameplay modifiers that add further depth and flexibility to the campaign.