Maintain a separate branch for each platform
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I'm trying to port my project to another platform and I've found a few differences between this new platform and the one I started on. I've seen the autotools package and configure scripts which are supposed to help with that, but I was wondering how feasible it would be to just have a separate branch for each new platform.

The only problem I see is how to do development on the target platform and then merge in changes to other branches without getting the platform-dependent changes. If there is a way to do that, it seems to me it'd be much cleaner.

Has anyone done this who can recommend/discourage this approach?