uthash: Include <stdio.h> when HASH_DEBUG is set.

This way the user doesn't have to `#include <stdio.h>` just because
someone on the command line did a `-DHASH_DEBUG`.

src/uthash.h

@@ -522,7 +522,8 @@ do {
  * This is for uthash developer only; it compiles away if HASH_DEBUG isn't defined.
  */
 #ifdef HASH_DEBUG
-#define HASH_OOPS(...) do { fprintf(stderr,__VA_ARGS__); exit(-1); } while (0)
+#include <stdio.h>   /* fprintf, stderr */
+#define HASH_OOPS(...) do { fprintf(stderr, __VA_ARGS__); exit(-1); } while (0)
 #define HASH_FSCK(hh,head,where)                                                 \
 do {                                                                             \
   struct UT_hash_handle *_thh;                                                   \

tests/test95.c

@@ -1,5 +1,5 @@
 #include <assert.h>
-#include <stdio.h>
+#include <stddef.h>   /* size_t, NULL */
 #include "utstack.h"
 
 typedef struct el {