lib/fs/readlink/: readlinknul(): Fix return type

Fixes: 419ce14b6f (2024-11-01, "lib/fs/readlink/: readlinknul(): Add function")
Cc: Serge Halyn <serge@hallyn.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/fs/readlink/readlinknul.c

@@ -7,7 +7,8 @@
 #include "fs/readlink/readlinknul.h"
 
 #include <stddef.h>
+#include <sys/types.h>
 
 
-extern inline int readlinknul(const char *restrict link, char *restrict buf,
+extern inline ssize_t readlinknul(const char *restrict link, char *restrict buf,
     size_t size);

lib/fs/readlink/readlinknul.h

@@ -22,12 +22,12 @@
 
 
 ATTR_STRING(1)
-inline int readlinknul(const char *restrict link, char *restrict buf,
+inline ssize_t readlinknul(const char *restrict link, char *restrict buf,
     size_t size);
 
 
 // Similar to readlink(2), but terminate the string.
-inline int
+inline ssize_t
 readlinknul(const char *restrict link, char *restrict buf, size_t size)
 {
 	size_t   ulen;