My anti-virus is (free) avast version 8.0.1489 and database 130804-0 on windows 7 64 bits.
The full name of libgdk file is the first time : libgdk-win32-2.0-0.dll and in the second scan the name is LIBGDK~1.DLL
The virus name is Win32:Evo-gen[Susp] in the folder C:\program Files (x86)\synfig\bin
My firewall is comodo and suggests me to block the program or use it in sandbox because it doesn’t know the editor.
edit : Finnally, it’s a false positve error Avast wrongly classifies an innocuous file as a virus but there is no risk of infection.