[NSKIP023] os.pipe() ENOSYS in standalone mode

[ada-x64]

[NSKIP023] os.pipe() ENOSYS in standalone mode

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NSKIP023: os.pipe() ENOSYS in standalone mode

Root cause

Standalone Nanvix does not implement the pipe(2) syscall — os.pipe()
returns errno 134 (ENOSYS). Hosted Nanvix (linuxd) supports pipes, so
this is a is_nanvix_standalone predicate.

Inline repro

import os
print(hasattr(os, 'pipe'))   # True (compiled in)
os.pipe()                    # OSError: ENOSYS on standalone

Finding the footprint

rg -n 'NSKIP023'

Parent

Tracked in #371.