Small fix to build on non-windows platforms.

scratchpad/img2ansi.cpp

@@ -11,7 +11,9 @@
 #include <ftxui/screen/terminal.hpp>
 #include <iostream>
 #include <fcntl.h>
+#if defined(_WIN64) || defined(_WIN32)
  #include <io.h>
+#endif
 #include <vector>
 
 using namespace std::chrono_literals;
@@ -67,7 +69,10 @@ HSVColor rgb_to_hsv(sf::Color rgb) {
 int main(int argc, char *argv[]) {
   ftxui::Terminal::SetColorSupport(ftxui::Terminal::Color::TrueColor);
 
+#if defined(_WIN64) || defined(_WIN32)
   _setmode(_fileno(stdout), _O_U16TEXT);
+#endif
+
   dbc::check(argc == 2, "USAGE: img2ansi <image_file>");
 
   string image_file(argv[1]);