[kallmek3nny]

What

Carry pushkarreddyy's original #3252 work onto current main, preserving the original author and behavior:

• add sigpending_nid_postfix, returning an empty pending set while AnyPS5 has no pending-signal queue
• add sigsuspend_nid_postfix, validating the mask pointer and returning EINTR without suspending yet
• add focused GuestSignals coverage for null pointers, the empty pending set, and EINTR
• record the remaining signal-semantics limitation in TechnicalDebt

This carries the implementation offered in #3253 / commit 0b35d74274feee860593a720ac6fd5a4d2b7c607. The source changes are kept semantically the same; the test declaration was forward-declared so the old patch builds against current main.

Tested

• Linux Release: guest_signal_tests builds successfully
• guest_signals passes with --repeat until-fail:3

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed in TechnicalDebt
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: none
• AI-assisted: yes

[github-actions]

Other open pull requests touch the same code. Merging one will break the other, or both implement the same thing. If this one builds on them, list them in Depends on.

Pull request	Conflicting files (lines on main)	Same exports	Same new files
#4138	core/libs/prx/libkernel/System/src/Signals.cpp L283-289
#4383	core/libs/tests/GuestSignals.cpp L9, L20 docs/dev/TechnicalDebt.md L490	sigpending_nid_postfix sigsuspend_nid_postfix
#4541	core/libs/tests/GuestSignals.cpp L9, L20 docs/dev/TechnicalDebt.md L490	sigpending_nid_postfix sigsuspend_nid_postfix

[github-actions]

Progress report (2a5eca1 → d03568f)

➖ System libraries: 86.34% (+0.0%, +2 implemented functions)

✅ 2 implemented

Library	Name
libkernel	sigpending_nid_postfix
libkernel	sigsuspend_nid_postfix