crtl: missing <netinet/tcp.h>, <netdb.h>, <poll.h> — ENet falls back to host headers

• Type: feature (crtl header surface). Track C.
• Found: 2026-07-08 game-library ladder, ENet probe (feature-game-library-candidate-suite).

Symptom

ENet's unix.c includes <netinet/tcp.h>, <netdb.h>, <poll.h> — none in lib/crtl/include, so the host copies are pulled, dragging a full host socket header set that redefines crtl's own struct in_addr and triggers bug-c-tag-redef-misfiles-field-selfref-segv.

Ask

Add minimal crtl headers: netinet/tcp.h (TCP_NODELAY + struct tcphdr subset), netdb.h (struct hostent/addrinfo + gethostby*/getaddrinfo decls — impls can be the not-found stubs already in socket.c), poll.h (struct pollfd, POLLIN/ POLLOUT, poll() over the PAL select/poll bridge). Also missing impls surfaced: sendmsg/recvmsg (unix.c uses them for scatter-gather I/O).

Gate

ENet unity compiles against crtl only (no host header fallback); enet_probe links + runs (after the tag-redef segv is fixed too).

Log

• 2026-07-08 — resolved, commit a69678dd.