Use size_t for realloc functions.

nettle-types.h

@@ -40,7 +40,7 @@ typedef void nettle_random_func(void *ctx,
 typedef void nettle_progress_func(void *ctx, int c);
 
 /* Realloc function, used by struct nettle_buffer. */
-typedef void *nettle_realloc_func(void *ctx, void *p, unsigned length);
+typedef void *nettle_realloc_func(void *ctx, void *p, size_t length);
 
 /* Ciphers */
 typedef void nettle_set_key_func(void *ctx,

realloc.c

@@ -35,7 +35,7 @@
    totally free the object, it is allowed to return a valid
    pointer. */
 void *
-nettle_realloc(void *ctx UNUSED, void *p, unsigned length)
+nettle_realloc(void *ctx UNUSED, void *p, size_t length)
 {
   if (length > 0)
     return realloc(p, length);
@@ -45,7 +45,7 @@ nettle_realloc(void *ctx UNUSED, void *p, unsigned length)
 }
 
 void *
-nettle_xrealloc(void *ctx UNUSED, void *p, unsigned length)
+nettle_xrealloc(void *ctx UNUSED, void *p, size_t length)
 {
   if (length > 0)
     {