POSIX-2024 says:
> There is no correlation between values of the st_blocks and
> st_blksize, and the f_bsize (from <sys/statvfs.h>) structure members.
Some code in Haiku has mixed that up in the past (e.g. the write_overlay).
This will allow a constant to be used instead, clarifying what's happening.
POSIX-2024 does not actually require this constant, but it does say:
> Traditionally, some implementations defined the multiplier for
> st_blocks in <sys/param.h> as the symbol DEV_BSIZE.
And indeed, glibc, musl, and FreeBSD (at least) all define it.
So it seems to make sense for us to do the same.
Related to #19251.
Augustin Cavalier
999bb2e88a