feat: add C implementation for `number/float32/base/signbit` #4319

	#/
	# @license Apache-2.0
	#
	# Copyright (c) 2024 The Stdlib Authors.
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.
	#/

	# Workflow name:
	name: labeler

	# Workflow triggers:
	on:
	pull_request_target:

	# Workflow jobs:
	jobs:

	# Define a job which automatically labels pull requests based on the contents of the pull request:
	labeler:

	# Define job name:
	name: 'Labeler'

	# Only run this job if the pull request did not have label `automated-pr`:
	if: contains(github.event.pull_request.labels.*.name, 'automated-pr') == false

	# Define job permissions:
	permissions:
	contents: read
	pull-requests: write

	# Define the type of virtual host machine:
	runs-on: ubuntu-latest

	# Define the sequence of job steps:
	steps:

	# Automatically label pull requests:
	- name: 'Automatically label pull requests'
	# Pin action to full length commit SHA
	uses: actions/labeler@8558fd74291d67161a8a78ce36a881fa63b766a9 # v5.0.0
	with:
	configuration-path: .github/labeler.yml
	repo-token: ${{ secrets.CHATBOT_GITHUB_TOKEN }}

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