Web Apocrypha

WebKitGtk+ cross compilation consists of two parts. First, you need a cross compiler and the library dependencies of WebKitGtk+. Next, you have to setup the build system properly. You can reach this with some wrapper scripts.

Toolchain

For the cross compilation you need a toolchain. In this post I use this GNU toolchain:

http://www.codesourcery.com/downloads/public/gnu_toolchain/arm-none-linu...

Unpack this to your toolchain directory. (e.g. ~/TOOLCHAIN)

Library dependencies

In my previous post, I've shown which libraries needed for WebKitGtk+ and how you can compile them. If you follow the steps given there, you can find the ARM target root dir at

~/scratchbox/users/arm-user/targets/DIABLO_ARMEL

There, you'll need these directories:

• lib
• usr/lib
• usr/include

Copy these directories to your sdk root. (e.g. ~/ARM-SDK)

If you want to compile these dependecies by hand, you can find the dependency list at http://trac.webkit.org/wiki/BuildingGtk.

In the ~/ARM-SDK/usr/lib directory, there are some *.la files. These files contain the library paths with a wrong prefix. You can fix them with the following script:

set_la_prefix.sh:

#!/bin/bash

#This script sets the prefixes in the .la files to SDKROOT
export SDKROOT="~/ARM-SDK"

prefixed_la="prefixed_la"

cd $SDKROOT/usr/lib
mkdir $prefixed_la

for filename in `ls -l | grep ^- | awk '{print $8}'`
do 
  cat $filename | \
  sed "s/'\/usr/'$(echo $SDKROOT | sed 's/\//\\\//g')\/usr/g" | \
  sed "s/ \/usr/ $(echo $SDKROOT | sed 's/\//\\\//g')\/usr/g" > $prefixed_la/$filename
done

mv $prefixed_la/* . 
rm -rf $prefixed_la

(In ~/ARM-SDK/usr/include there are some system headers, which may cause some compilation errors since the toolchain contains these headers too, but if you delete these from your sdk, the errors will be gone.)

Wrapper scripts

For the WebKitGtk+ cross compilation, you need some wrapper scripts:

pkg-config:

#!/bin/bash

export PKG_CONFIG_LIBDIR="$SDKROOT/usr/lib/pkgconfig"
/usr/bin/pkg-config --define-variable=prefix=$SDKROOT/usr $@

icu-config:

#!/bin/bash

/usr/bin/icu-config --prefix=$SDKROOT/usr $@

Put these scripts to a cross binary directory e.g. ~/CROSS_BIN, (And don't forget to give them executing permission.)

Cross compilation script

Now, you just need a build script that integrates these.

build-webkit.sh:

#!/bin/bash

export SDKROOT="~/ARM-SDK"
export TOOLCHAIN="~/TOOLCHAIN/arm-2008q3"
export PATH="~/CROSS_BIN:$PATH"

export CPPFLAGS="-I$SDKROOT/usr/include"
export LIBS="$LIBS -L$SDKROOT/lib -L$SDKROOT/usr/lib"

export CC="$TOOLCHAIN/bin/arm-none-linux-gnueabi-gcc"
export CXX="$TOOLCHAIN/bin/arm-none-linux-gnueabi-g++"
export LINK="$TOOLCHAIN/bin/arm-none-linux-gnueabi-g++"
export LINK_SHLIB="$TOOLCHAIN/bin/arm-none-linux-gnueabi-g++"
export AR="$TOOLCHAIN/bin/arm-none-linux-gnueabi-ar"
export OBJCOPY="$TOOLCHAIN/bin/arm-none-linux-gnueabi-objcopy"
export STRIP="$TOOLCHAIN/bin/arm-none-linux-gnueabi-strip"

export BUILD_WEBKIT_ARGS="--host=arm-none-linux-gnueabi --build=i686-pc-linux-gnu --target=arm"

cd ~/WebKit

WebKitTools/Scripts/build-webkit --gtk --release

If you've set up everything properly, you can cross compile the WebKitGtk+ without any emulators.