Don't include stdint.h anywhere

This should have fixed by commit 28682322, but there was one #include
left in utf.c. It now includes utf.h instead of stdint.h.

src/utf.c

@@ -6,7 +6,7 @@
  */
 
 #include <string.h>
-#include <stdint.h>
+#include "utf.h"
 
 int utf8_encode(int32_t codepoint, char *buffer, int *size)
 {