= Set up a cross-build machine for the Raspberry Pi =

== Prerequisites ==

This document focuses on Debian hosts. Debian derivatives such as Ubuntu should work with minor changes.

== Downloads ==

 * Download the [https://github.com/raspberrypi/firmware/downloads firmware] (.tar.gz)
 * Download the [https://github.com/raspberrypi/tools/downloads build tools] (.tar.gz)

Alternatively, these can be retrieved using Git. Unpack them in two directories called `firmware` and `tools`.

== Environment variables ==

 * Set `RASPI_SDK_ROOT` to the directory containing `firmware` and `tools`.
 * Add the following directory to `PATH`:

{{{
#!sh
$RASPI_SDK_ROOT/tools/arm-bcm2708/arm-bcm2708hardfp-linux-gnueabi/bin
}}}

== Building autoconf projects ==

For simple autoconf projects (using `./configure ; make`) the following command can now be used:

{{{
#!sh
RASPI_INCLUDES="$RASPI_SDK_ROOT/firmware/opt/vc/include"
RASPI_LIBS="$RASPI_SDK_ROOT/firmware/opt/vc/lib"

./configure --host=arm-bcm2708hardfp-linux-gnueabi \
    CPPFLAGS="-I$RASPI_INCLUDES -I$RASPI_INCLUDES/interface/vcos/pthreads" \
    LDFLAGS="-L$RASPI_LIBS"

make
}}}

== Using Debian / Raspbian libraries ==

Choose a directory to store Raspbian packages, for instance `$RASPI_SDK_ROOT/chroot`. You can then use `debootstrap` to install packages to it, but if you have a multiarch-enabled system you can use this poor man's shell script:

{{{
#!sh
raspi-install () {
    for pkg in "$@"
    do
        apt-get download "$pkg":armhf \
         && dpkg-deb -x "$pkg"_*.deb $RASPI_SDK_ROOT/chroot \
         && rm -f "$pkg"_*_armhf.deb
    done
}
}}}

Then for ''eg.'' SDL:

{{{
#!sh
raspi-install libsdl1.2debian libsdl1.2-dev
}}}

Then add the following to `CPPFLAGS` in the configure line:

{{{
#!sh
-I$RASPI_SDK_ROOT/root/usr/include
}}}

And the following to `LDFLAGS`:

{{{
#!sh
-L$RASPI_SDK_ROOT/chroot/lib/arm-linux-gnueabihf
-Wl,-rpath-link -Wl,$RASPI_SDK_ROOT/chroot/lib/arm-linux-gnueabihf
-L$RASPI_SDK_ROOT/chroot/usr/lib/arm-linux-gnueabihf
-Wl,-rpath-link -Wl,$RASPI_SDK_ROOT/chroot/usr/lib/arm-linux-gnueabihf
-Wl,--unresolved-symbols=ignore-in-shared-libs
}}}

== Bitten configuration ==

For Lol Engine autobuilders, add the following section to the bitten machine file:

{{{
#!ini
[raspi]
version = 0
}}}