Sergiocampama  tipped us about his Uniarch tutorial in the Forums.

Uniarch is an initiative to unify all the work left behind by mspgcc3 and mspgcc4, while also separating the boundaries between the compiler and TI header files. This ‘branch’ of mspgcc is the most advanced one, having over 300 supported MSP430 devices.

I have updated the guide and it now builds up to today’s version.

Make sure you check out his projects at his Github.