build.yml: add -Wextra for CI build #439

	name: Build

	on:
	push:
	breanches:
	- main
	paths:
	- 'src/**'
	- 'include/**'
	- 'tools/src/**'
	- 'Makefile'
	- '*.mk'
	- '.github/workflows/build.yml'

	pull_request:
	paths:
	- 'src/**'
	- 'include/**'
	- 'tools/src/**'
	- 'Makefile'
	- '*.mk'
	- '.github/workflows/build.yml'

	jobs:

	build:
	name: Build library

	runs-on: ubuntu-latest
	env:
	CC: gcc
	CFLAGS: -Os -Wall -Wextra -std=c99
	steps:
	- uses: actions/checkout@v4

	- name: Build static library
	run: make static

	- name: Build shared library
	run: make shared

	- name: Compile solsys variants
	run: make solsys

	- name: Generate CIO locator data
	run: make cio_file

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