First of all let me thank you for your reply.
I just have 3 questions on what you have replied to me:
2- If I want to deliver this executable to other persons (with Windows7) I have to also include this dll in the package right?
3- in my mingw-w64 folder I have two folders with binaries: /bin and a folder x86_64-w64-mingw32
If I want to generate 64bit binaries which one shall I sue?