You don't have to port you simple app on windows, it is simple enough and doesn't contain and system dependent part.
You should just download latest libraw binary and compile your app with proper toolchain (mignw or visual studio) and use proper include and library options during compilation (-I"your_libraw_include_path" -L"your_libraw_lib_path" -lraw options for mingw/gcc or "Additional Include directories" "Additional Library directories" and "Additional libraries" for Visual studio project settings)