So far, AVISPA is not in the portage tree (of course) and there's no overlay that has this app. So you have to download the app from AVISPA web site http://www.avispa-project.org
AVISPA is only available as precompiled 32bits bianary, so you have no choice but to download and install it manually (you need to register to download).
Once downloaded, just extract it to a directory your home:
[code]cd ~
tar xvzf avispa-package-1.1_Linux-i686.tgz[/code]
The precompiled 32bits SPAN does not work on x86_64 arch, if you run it, you will get something like:
[code]./span: error while loading shared libraries: libtk8.4.so: wrong ELF class: ELFCLASS64[/code]
Then you have to build it
To build SPAN, you'll need dev-lang/tk and dev-lang/ocaml, so emerge them:
[code]emerge -av dev-lang/tk dev-lang/ocaml[/code]
Now you need to get SPAN from here http://www.irisa.fr/lande/genet/span/span-1.1-source.tar.gz
Put it somewhere you can remember, for example ~/Desktop
Now extract span to a directory, let's say ~/
[code]cd ~
tar xvzf span-1.1-source.tar.gz[/code]
You'll have a dicrectory named span
[code]cd span
make[/code]
If it complains, then you need to set following environment variable:
[code]export AVISPA_PACKAGE=~/avispa-1.1
export SPAN=~/span[/code]
Once compiled, you're ready to run SPAN:
[code]./span[/code]
If span cannot find OFMC, ATSE, TA4SP... libs or config files, just copy the respective directories and files from ~/avispa-1.1/bin/backends to ~span/bin/backends
I'll make an ebuild for SPAN once I have time.