inet_gethost aborts (FORTIFY FD_SET >= FD_SETSIZE 1024) on Android x86_64

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Summary

On an Android x86_64 target, the inet_gethost helper from the bundled OTP
runtime aborts under Android's FORTIFY runtime check:

inet_gethost[<pid>]: WARNING:Unable to write to child process.
FORTIFY: FD_SET: file descriptor 28872 >= FD_SETSIZE 1024
F DEBUG : Cmdline: /data/.../files/otp/erts-17.0/bin/inet_gethost 4
F DEBUG : pid: <pid>, name: inet_gethost
F DEBUG : #03 pc ... /data/app/.../lib/x86_64/libinet_gethost.so

inet_gethost calls FD_SET(fd, ...) with an fd (28872 in this run) that
exceeds FD_SETSIZE (1024). Android's FORTIFY (_FORTIFY_SOURCE) turns the
out-of-range FD_SET into a SIGABRT.

Impact

Non-fatal — the BEAM and the app keep running (the helper is re-spawned), but
name resolution routed through inet_gethost fails/retries and the helper
crashes repeatedly. Observed during normal startup, right after the app came up
and dialed its backend.

Environment

• ABI: x86_64 (Android 13, running under Waydroid on Linux)
• OTP runtime: otp-android-x86_64-5c9c69fc, erts-17.0
• libinet_gethost.so from the app's lib/x86_64/

Likely cause

inet_gethost (erts) uses select() / FD_SET on its inherited communication
fd. On Android, app processes routinely hold very high fd numbers, so the
inherited fd can exceed FD_SETSIZE (1024) and overflow fd_set. This is an
erts-level concern (inet_gethost.c) and could in principle affect any Android
ABI where the helper inherits a high fd — x86_64 just made it reproducible here.

Possible directions:

• build/patch the bundled erts inet_gethost to use poll() instead of
  select() / FD_SET (discussed upstream in OTP), or
• dup the helper's communication fd below FD_SETSIZE before it runs.

Repro

1. Build + deploy a mob app for x86_64 (mix mob.deploy --native, abiFilters
   including x86_64).
2. Launch on an x86_64 Android target (e.g. Waydroid).
3. Watch logcat (BEAMout / inet_gethost / DEBUG) during startup — the
   FORTIFY abort fires when a hostname lookup is routed through the helper.

Observed while standing up an x86_64 Waydroid CI target. Happy to attach a full
erl_crash.dump / logcat if useful.