[Galaxy S 4 Mini Android Development] sysKin:
Good news, everybody! I just finished booting my yesterday's build, made with GCC 4.8.5, provided by SaberMod. Moreover, I achieved that in a way that is not hacky at all!

Using SaberMod toolchain to build your CM12

We will use |repo|'s manifest capability to put SaberMod's eabi and androideabi 4.8.5 toochains directly in place of existing gcc toolchains.

a) navigate to ~/android/system/.repo/local_manifests (if you're using a GUI you might need to change its settings to show hidden files/folders)

b) create a new file named "sabermod.xml". You can give it a different name as long as it ends with .xml

c) make its contents the following:

<manifest>
<remove-project name="platform/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.8"/>
<remove-project name="platform/prebuilts/gcc/linux-x86/arm/arm-eabi-4.8"/>
<project name="SaberMod/arm-eabi-4.8" path="prebuilts/gcc/linux-x86/arm/arm-eabi-4.8" remote="github" revision="master"/>
<project name="SaberMod/arm-androideabi-4.8" path="prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.8" remote="github" revision="master"/>
</manifest>

d) execute |repo sync|. Warning: it will take a while, and will download about 1.5 GB. [edit] much less after commit squash 16 hours ago, but now it has some trouble syncing. weird [/edit]

e) just |brunch serranoltexx| again! Since we haven't changed any paths anywhere, no modifications to envsetup.sh nor makefiles are needed :)

It's borked! I am on Ubuntu 14.4 and ld doesn't run because of missing libstdc++.so.6(GLIBCXX_3.4.20)

Indeed, the toolchain was itself compiled with bleeding-edge gcc 4.9 and therefore requires gcc 4.9's standard c libs. Make sure you have gcc 4.9 (sudo apt-get install gcc-4.9; you'll probably have it) and then do the following:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get upgrade

It's borked! I am on Ubuntu and cc1 doesn't run because of missing libisl.so.13!

Indeed. Do what they say here to add 'vivid' repository: http://packages.ubuntu.com/vivid/amd64/libisl13/download

followed by

sudo apt-get update
sudo apt-get install libisl13

It's borked! I'm on some other distro and libraries are missing

Well... Ask here, maybe someone will know. Or if you do solve it yourself, tell us how :)

Is it any better?

I have no idea! All benchmarks are too noisy for me to say anything definite without spending a day on statistical analysis. But GCC 4.8.4's changelog indicates a lot of fixes to inline heuristics and other optimisations, so it *should* be, in theory, better.

What's the deal with eabi and androideabi?

eabi is used to build linux kernel. If you're using F4k's kernel you can skip that part.

androideabi is used to build the rest of android. It's the one that matters.

As mentioned above, linaro squished eabi and androideabi toolchain to a single toolchain (because why would they differ?? they're the same gcc and friends after all), but we're not using linaro here.

GCC 4.9?

I will play with 4.9 next. I expect it to work fine for kernel, but it might or might not work for androideabi.

This is just GCC and friends. Are there any other tools that matter?

There is clang! And its base project LLVM. Clang is on version 3.7 while we're using 3.3, so there is definitely something here. They do exist in SaberMod repository, so I will attempt to replace them later (and if someone wants to beat me to it, go ahead!)