Compiling iGraph from Sources
GraphML support is an optional component of iGraph. iGraph uses libxml2 to read GraphML files and thus if you want GraphML support, libxml2 must be installed in your system before compiling iGraph.
libxml2 is available from http://xmlsoft.org/
If you install libxml2 to a non-standard directory (for example, by using the --prefix option during ./configure) then you will need to inform iGraph's ./configure of this location.
For example, I installed libxml2 to $HOME/system by executing ./configure --prefix=$HOME/system before compiling libxml2.
In order for iGraph to find this directory, I had to specify it by executing
./configure --prefix=$HOME/system LDFLAGS=-L$HOME/system/lib/ CPPFLAGS=-I$HOME/system/include.
Howevever, this was insufficient when I came to compile the R interface. To enable GraphML processing within R I had to export the variables:
export CPPFLAGS=-I$HOME/system/include export LDFLAGS=-L$HOME/system/lib/ ./configure --prefix=$HOME/system}}
Compiling the Development Version
iGraph's development version can be found at LaunchPad (https://launchpad.net/igraph). To obtain the sources you need to install the python-based "Bazaar" version control system. Once installed, enter bzr branch lp:igraph/0.5-main to download the latest version of the 0.5 trunk.
For steps on how to compile the library see Developers' Information