Ok, you almost got it. Let's do this the way I would--not that I'm an expert but this seems to work for me.
We're going to clone rbrune's magic-lantern repository--hope that's ok with you Rafael. The reason we're cloning instead of forking is because we want to see his updates in SourceTree as he pushes his commits. Also, we won't be making any pull requests. That's another topic.

Go to rburne's bitbucket page and copy the URL.
https://bitbucket.org/rbrune/magic-lantern

Paste the address into SourceTree.

Note that it will create a local repository with the same name as rbrune's repository name,
magic-lantern. This could be confusing if you are cloning and forking various repositories so in order to keep things organized we'll append rburne to your local repository.

When you open up his repository in SourceTree you'll see his latest commits at the top but caution because you aren't in the right branch yet, you're in the default branch--check the panel on the left.

Double click either on the panel on the left or the graphic display of his workflow to get into the branch that you want. In this case you'll want his
crop_rec_raw_video_10bit_12bit branch.

Ok, now you can navigate through the local repository with the terminal, saved in your home directory if you followed this tutorial.
I've got an idea what's going on with gcc-5 because of something that happened to me just this morning. Try this first:
which gcc-5
If you get nothing, check that it is installed:
brew search gcc
This is what I got:
cosmo0920/mingw_w64/i686-w64-mingw32-gcc ✔
cosmo0920/mingw_w64/x86-64-w64-mingw32-gcc
gcc ✔
homebrew/dupes/apple-gcc42 ✔
homebrew/versions/gcc43
homebrew/versions/gcc44
homebrew/versions/gcc45
homebrew/versions/gcc46
homebrew/versions/gcc47
homebrew/versions/gcc48
homebrew/versions/gcc49 ✔
homebrew/versions/gcc5 ✔
homebrew/versions/gcc6
homebrew/versions/llvm-gcc28
Caskroom/cask/gcc-arm-embedded
Note that the check marks show what's installed. If you have a check mark on gcc6 and gcc that means that you're linked to gcc6. That isn't working with ML at this time so link to gcc5:
brew link gcc5
Now try this again:
which gcc-5
You should get this:
/usr/local/bin/gcc-5
Got all that? Ok--let's see if you can compile all those platforms. They should all work except for 1100D.105 and don't bother with 7D_MASTER.203, not sure what that one is for.