Solve error: Cannot open include file: 'X11/Xlocale.h': No such file or directory

 

When you use FLTK with VS2010, you may get the error: fatal error C1083: Cannot open include file: 'X11/Xlocale.h': No such file or directory.

 

The way to solve this is quite simple, just add the following line before '#include <FL/Fl.H>'

#define WIN32