erofs-freebsd-out-tree/docs/pre13-low-c2.md

Pre13 L-C2

The two planned zero-length on-disk tail arrays now use standard flexible array declarators:

• erofs_xattr_ibody_header::h_shared_xattrs
• erofs_xattr_long_prefix::infix

The layout probe retains the previous [0] declarations and asserts equal structure size/alignment and member offsets. Host Clang accepts both old and new declarations with the same warning/error result and identical layouts. The probe is also retained for the final FreeBSD guest compiler gate.

No KLD build, QEMU, smoke, or feature test was run for this batch.