rootless: use SYS_renameat2 instead of __NR_renameat2
use the correct definition for the syscall number.
int renameat2 (int olddirfd, const char *oldpath, int newdirfd, const char *newpath, unsigned int flags)
{
-# ifdef __NR_renameat2
- return (int) syscall (__NR_renameat2, olddirfd, oldpath, newdirfd, newpath, flags);
+# ifdef SYS_renameat2
+ return (int) syscall (SYS_renameat2, olddirfd, oldpath, newdirfd, newpath, flags);
# else
/* no way to implement it atomically. */
errno = ENOSYS;
