fixed some `-Wsuggest-attribute=returns_nonnull` GCC warnings (#6950) #13982

	# Syntax reference https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions
	# Environment reference https://help.github.com/en/actions/reference/virtual-environments-for-github-hosted-runners
	name: CI-cygwin

	on:
	push:
	branches:
	- 'main'
	- 'releases/**'
	- '2.*'
	tags:
	- '2.*'
	pull_request:

	permissions:
	contents: read

	defaults:
	run:
	shell: cmd

	jobs:
	build_cygwin:
	strategy:
	matrix:
	os: [windows-2022]
	arch: [x64]
	include:
	- platform: 'x86_64'
	packages: \|
	gcc-g++
	python3
	fail-fast: false

	runs-on: ${{ matrix.os }}

	steps:
	- uses: actions/checkout@v4
	with:
	persist-credentials: false

	- name: Set up Cygwin
	uses: cygwin/cygwin-install-action@master
	with:
	platform: ${{ matrix.arch }}
	packages: ${{ matrix.packages }}

	# Cygwin will always link the binaries even if they already exist. The linking is also extremely slow. So just run the "check" target which includes all the binaries.
	- name: Build all and run test
	run: \|
	C:\cygwin\bin\bash.exe -l -c cd %GITHUB_WORKSPACE% && make VERBOSE=1 -j2 check

	- name: Extra test for misra
	run: \|
	cd %GITHUB_WORKSPACE%\addons\test
	..\..\cppcheck.exe --dump -DDUMMY --suppress=uninitvar --inline-suppr misra\misra-test.c --std=c89 --platform=unix64
	python3 ..\misra.py -verify misra\misra-test.c.dump
	..\..\cppcheck.exe --addon=misra --enable=style --inline-suppr --enable=information --error-exitcode=1 misra\misra-ctu-1-test.c misra\misra-ctu-2-test.c

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