POSIX-2024 and dirent.h

Hi

POSIX Issue 8 (2024) adds the following to dirent.h:

DT_BLK, DT_CHR, DT_DIR, DT_FIFO, DT_LNK, DT_REG, DT_SOCK, DT_UNKNOWN,
DT_MQ, DT_SEM, DT_SHM, and DT_TMO

These were not mentioned in POSIX Issue 7 (2018).

The default dirent.h and sys/dirent.h do not support anything. I only see
the DT_ constants in the sys/rtems version.

The sys/rtems version has the constants inside a __BSD_VISIBLE guard.

I think these should also be under a (_POSIX_C_SOURCE >= 202405L) guard.

I am looking for concurrence and whether adding a check for 202405L has any
impact on sys/features.h. POSIX-2018 (Issue 7) still specifies
using 200809L for _POSIX_C_SOURCE.

Thanks for any feedback.

--joel