delete unused returned variable from gauss_newton() #185

	name: cpu-linux-build-and-test

	on:
	push:
	paths-ignore:
	- '**.md'
	- 'images/**'
	pull_request:
	paths-ignore:
	- '**.md'
	- 'images/**'

	jobs:
	build:
	strategy:
	matrix:
	config: [ '', '-DPBRT_DBG_LOGGING=True', '-DPBRT_FLOAT_AS_DOUBLE=True' ]
	compilers:
	- {
	cc: "gcc-9",
	cxx: "g++-9",
	}
	- {
	cc: "gcc-10",
	cxx: "g++-10",
	}
	- {
	cc: "clang-10",
	cxx: "clang++-10",
	}
	- {
	cc: "clang-11",
	cxx: "clang++-11",
	}
	# WAR github actions flakiness
	# - {
	# cc: "clang-12",
	# cxx: "clang++-12",
	# }

	fail-fast: false

	runs-on: ubuntu-20.04
	name: Build and test ${{ matrix.compilers.cxx }} - ${{ matrix.config }}

	steps:
	- name: Checkout pbrt
	uses: actions/checkout@v3
	with:
	submodules: true

	- name: Checkout rgb2spectrum tables
	uses: actions/checkout@v3
	with:
	repository: mmp/rgb2spectrum
	path: build

	- name: Get cmake
	uses: lukka/get-cmake@latest

	- name: Install OpenEXR
	run: sudo apt-get -y install libopenexr-dev

	- name: Install OpenGL
	run: sudo apt-get install -y --no-install-recommends libx11-dev libxcursor-dev libxrandr-dev libxinerama-dev libxi-dev libxext-dev libxfixes-dev libgl1-mesa-dev

	- name: Install compilers
	run: sudo apt-get -y install ${{ matrix.compilers.cc }} ${{ matrix.compilers.cxx }}

	- name: Configure
	run: \|
	cd build
	env CC=${{ matrix.compilers.cc }} CXX=${{ matrix.compilers.cxx }} cmake .. -DPBRT_USE_PREGENERATED_RGB_TO_SPECTRUM_TABLES=True ${{ matrix.config }}

	- name: Build
	run: cmake --build build --parallel --config Release

	- name: Test
	if: ${{ matrix.config == '' }}
	run: ./pbrt_test
	working-directory: build

Provide feedback