Use the z-option to printf %d for size_t printf. z is supported by the

libcurl *printf and by Linux printf(). This should make the code work nicely
even for 64bit size_ts.

src/main.c

@@ -2427,11 +2427,11 @@ void dump(const char *text,
     /* without the hex output, we can fit more on screen */
     width = 0x40;
 
-  fprintf(stream, "%s, %d bytes (0x%x)\n", text, size, size);
+  fprintf(stream, "%s, %zd bytes (0x%zx)\n", text, size, size);
 
   for(i=0; i<size; i+= width) {
 
-    fprintf(stream, "%04x: ", i);
+    fprintf(stream, "%04zx: ", i);
 
     if(!nohex) {
       /* hex not disabled, show it */