====== Building the GCW Zero Toolchain ======

For our [[https://ci.easyrpg.org/|Jenkins build server]] we needed a modified toolchain, that does not depend to be installed in ''/opt''.
The following instructions have been written along the way and should result in a working toolchain that is suitable to get a working EasyRPG Player build.

//Prerequisites//: I assume you do all the steps in a seperate build directory to not interfere with old toolchains and other stuff. Also you need some development tools installed on your machine, for example ''gcc'', ''make'' and ''subversion''. The buildroot will warn you, when you forgot to install something, though.

First, we need the buildroot from GitHub and change into the directory:

<code bash>
git clone https://github.com/gcwnow/buildroot.git
cd buildroot
</code>

To use the default configuration:

<code bash>
make gcw0_defconfig
</code>

**Optionally**, we can use a previously saved config file, just copy it to ''.config''.
We need to add newly available options then:
<code bash>
make oldconfig
</code>

We configure the packages to be build and available options:
<code bash>
make menuconfig
</code>
There are also the graphical frontends ''xconfig'', using qt and ''gconfig'', using gtk.

Most of the libraries and stuff under "Target Packages" are not needed, so we disable them to save some time while compiling.
Needed libraries are ''sdl'', ''sdl_mixer'' and ''icu''.

Now the important step: change the toolchain directory from ''/opt/gcw0-toolchain'' to your desired directory under "Build Options" --> "Host Dir".
(''BR2_HOST_DIR="/home/jenkins/gcw0-toolchain"'' in .config)

To speed up the build further, set the parallel make jobs to the cores of your cpu "Number of jobs to run simultaneously (0 for auto)".
(''BR2_JLEVEL=2'' in .config)

To speed up possibly rebuilds, enable ''ccache'' "Enable compiler cache".
(''BR2_CCACHE=y'' and ''BR2_CCACHE_DIR="$(HOME)/.buildroot-ccache"'' in .config)

When all things are set up, we can start the build and get something to drink in the meanwhile =)
<code bash>
nice -n19 make
</code>

Afterwards, there should be a new, shiny toolchain in the directory you chose.

===== Cross-compile pixman =====

Pixman is a needed library and not part of the toolchain.

Download [[http://cairographics.org/releases/|the latest release]] and extract it.

Then it is the normal auto-tools-based build steps:

<code bash>
cd pixman-*/
./configure --host=mipsel-linux --prefix=/usr
make
make DESTDIR=/home/jenkins/gcw0-toolchain/usr/mipsel-gcw0-linux-uclibc/sysroot/ install
</code>

Be sure to install it in the sysroot directory to ensure it is found when compiling target packages.