* dirent/Makefile (routines): Add scandir64, alphasort64, and
versionsort64.
* dirent/alphasort64.c: New file.
* dirent/scandir64.c: New file.
* dirent/versionsort64.c: New file.
* dirent/dirent.h: Add LFS support for scandir, alphasort, and
versionsort.
* sysdeps/generic/readdir64.c: Rename to __readdir64 and make
old name weak alias.
* sysdeps/unix/sysv/linux/readdir64.c: Likewise.
* dirent/alphasort.c: Use strcoll instead of strcmp.