Your best bet is to build with GCC under Linux - then it'll 'just work' for the boards it's designed for. If you're trying to use it with some other board then you'll probably have a hard time - you'll need to implement support for all the IO and timekeeping. There's some info on porting in the Readme in the GitHub repo.
If you need to use Visual Studio you'll have to look at the Makefile and then figure out what you need to add to your visual studio project to emulate what it's doing.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Your best bet is to build with GCC under Linux - then it'll 'just work' for the boards it's designed for. If you're trying to use it with some other board then you'll probably have a hard time - you'll need to implement support for all the IO and timekeeping. There's some info on porting in the Readme in the GitHub repo.
If you need to use Visual Studio you'll have to look at the Makefile and then figure out what you need to add to your visual studio project to emulate what it's doing.