Add mind mapping tool XMind.

This is a FOSS project, but this expression is using the binary build.
>> +    # append to startup configuration
>> +    ini=$out/XMind_Linux_64bit/XMind.ini
>
>It does. The binary also has build for linux 32, windows and mac, but i've not got those platforms and cannot test them.

Do you know about pkgsi686Linux.* in NixPkgs? You can download and
install 32-bit libraries on 64-bit systems without any problems.