examples: fix builds on windows

examples/code128.c

@@ -13,6 +13,10 @@
 
 #include <pdfio.h>
 #include <pdfio-content.h>
+#ifdef _WIN32
+#include <io.h>
+#include <fcntl.h>
+#endif
 
 
 //

examples/md2pdf.c

@@ -25,6 +25,7 @@
 #include <math.h>
 #ifdef _WIN32
 #  include <io.h>
+#  include <fcntl.h>
 #else
 #  include <unistd.h>
 #endif // _WIN32