ffi/posix: minor cleanup

Author: benoit-pierre

ffi/posix_h.lua

@@ -57,7 +57,7 @@ int mq_open(const char *, int, ...);
 ssize_t mq_receive(int, char *, size_t, unsigned int *);
 int mq_close(int);
 int close(int);
-off_t lseek(int fildes, off_t offset, int whence);
+off_t lseek(int, off_t, int);
 int fcntl(int, int, ...);
 int execl(const char *, const char *, ...);
 int execlp(const char *, const char *, ...);