Added a workaround for printing size_t.

docs/examples/ftpupload.c

@@ -32,6 +32,7 @@
 #else
 #include <unistd.h>
 #endif
+#include "printf_macro.h"
 
 /*
  * This example shows an FTP upload, with a rename of the file just after
@@ -56,7 +57,7 @@ static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *stream)
      by default internally */
   size_t retcode = fread(ptr, size, nmemb, stream);
 
-  fprintf(stderr, "*** We read %d bytes from file\n", retcode);
+  fprintf(stderr, "*** We read %" _FMT_SIZE_T " bytes from file\n", retcode);
   return retcode;
 }