Pulls in the three follow-up fixes that close the build-break
cascade left behind by the R17 'drop libc' commit (502c82bb):
1. Cargo.toml: __libc_only_for_layout_checks pinned to 0.2.149
(was 0.2.189 which pulled a release-abi-incompatible libc).
2. ld_so/dso.rs: panic!('static_relocate: unsupported relocation
type') rewritten to Result::Error via None::<()>.read_error(...)?.
DSO load failures now surface cleanly to the loader instead
of crashing init with SIGABRT.
3. platform/redox/socket.rs: refreshed MSG_NOSIGNAL docs to
describe the actual implementation (flag forwarding to
netstack scheme + netstack-side signal-mask blocking at
netstack/src/scheme/tcp.rs:66) instead of the stale 'strip
the flag' workaround description.
Verified by 'repo cook relibc' from a state that previously
reported three ld_so/socket compile errors; this bump lets
relibc ship clean end-to-end without depending on the libc
crate.
vasilito
7be983e311