The instructions in contributing mention:
Either one of the following:
- Visual C++ 2015 Build Tools containing standalone compilers, libraries and scripts
- Install the windows-build-tools via npm with npm install --global windows-build-tools
- Visual Studio Community 2015 (free) (other editions, like Professional and Enterprise, should work too) NOTE: Visual Studio 2015 doesn't install C++ by default. You have to rerun the setup, select "Modify" and then check Visual C++ -> Common Tools for Visual C++ 2015 (see http://stackoverflow.com/a/31955339)
My understanding is that you are using Visual Studio Community 2015, did you make sure to install Visual C++ 2015 through that? If so, did you also try using the npm package described in the second option?
Also, please make sure you have all the following mingw packages installed:
One more thing: may I ask why you are trying to build etcher from scratch? Keep in mind you can download any release from https://github.com/balena-io/etcher/releases (or the latest from the website). If you are looking to contribute to Etcher, please consider opening an issue directly on https://github.com/balena-io/etcher as it should get you in contact with the maintainers directly.