Yes it's true, the EOS code is available for all to clone/fork.
Here's a couple of quick notes on things I stumbled getting this first round to build. Note, I am assuming you have a basic understanding of how to use git, cmake, etc.
Remember to fetch submodules, this is your 1-2 punch before doing anything else :
git clone https://github.com/EOSIO/eos.git
git submodule update --init --recursive
I am using a mac to build, so initially I tried cmake -G Xcode but ran into too many issues so I switched to cmake -G "Unix Makefiles" in a separate workspace.
This could be Xcode related but I couldn't use OpenSSL 1.1.0f, I had to revert to OpenSSL 1.0.2.
there are several directories currently flagged as [incomplete][no build]. These may
contain non-compiling code. Use "make -k" or whatever "keep compiling after an error" option is available for your build environment.
the latest code is in the "refactor" branch.
Nothing runs yet, so refrain from pelting 
Finally, a nod to
Cheers!
-Phil
