Error when using the command python3 -m pip install -r requirements.txt

Running setup.py install for Pillow ... error
ERROR: Command errored out with exit status 1:
command: /Library/Frameworks/Python.framework/Versions/3.8/bin/python3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-install-gtdo_7kf/Pillow/setup.py'"'"'; __file__='"'"'/private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-install-gtdo_7kf/Pillow/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-record-kif646zv/install-record.txt --single-version-externally-managed --compile
cwd: /private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-install-gtdo_7kf/Pillow/
Complete output (175 lines):
running install
running build
running build_py
creating build
creating build/lib.macosx-10.9-x86_64-3.8
creating build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/MpoImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageMode.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PngImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/XbmImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PcxImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/SunImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageFile.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/SpiderImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/TarIO.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/FitsStubImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/MpegImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/BdfFontFile.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/GribStubImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageStat.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PixarImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/GimpPaletteFile.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageColor.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ContainerIO.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/MspImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/MicImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/_version.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImtImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/GifImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PalmImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageQt.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageMath.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PaletteFile.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/FontFile.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PdfParser.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ExifTags.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageCms.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/FpxImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageChops.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/BufrStubImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PSDraw.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PcdImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageFilter.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageDraw2.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImagePath.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/DcxImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/__init__.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/JpegPresets.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/Hdf5StubImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/features.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageDraw.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/GimpGradientFile.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageWin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/IcoImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/_tkinter_finder.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/EpsImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/TgaImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageMorph.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/Jpeg2KImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/WalImageFile.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PcfFontFile.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/BlpImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageTk.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/GbrImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageOps.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PdfImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageShow.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageEnhance.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/WmfImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageGrab.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/WebPImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/FliImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/TiffTags.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/CurImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/_util.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/GdImageFile.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/TiffImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/IptcImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImagePalette.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/BmpImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageTransform.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/IcnsImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/McIdasImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/XpmImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/OleFileIO.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/DdsImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageSequence.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PyAccess.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/_binary.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/Image.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/XVThumbImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/SgiImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PsdImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/JpegImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/ImageFont.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/PpmImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
copying src/PIL/FtexImagePlugin.py -> build/lib.macosx-10.9-x86_64-3.8/PIL
running egg_info
writing src/Pillow.egg-info/PKG-INFO
writing dependency_links to src/Pillow.egg-info/dependency_links.txt
writing top-level names to src/Pillow.egg-info/top_level.txt
reading manifest file 'src/Pillow.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
warning: no files found matching '*.c'
warning: no files found matching '*.h'
warning: no files found matching '*.sh'
no previously-included directories found matching 'docs/_static'
warning: no previously-included files found matching '.appveyor.yml'
warning: no previously-included files found matching '.coveragerc'
warning: no previously-included files found matching '.codecov.yml'
warning: no previously-included files found matching '.editorconfig'
warning: no previously-included files found matching '.landscape.yaml'
warning: no previously-included files found matching '.travis'
warning: no previously-included files found matching '.travis/*'
warning: no previously-included files found matching 'tox.ini'
warning: no previously-included files matching '.git*' found anywhere in distribution
warning: no previously-included files matching '*.pyc' found anywhere in distribution
warning: no previously-included files matching '*.so' found anywhere in distribution
writing manifest file 'src/Pillow.egg-info/SOURCES.txt'
running build_ext


The headers or library files could not be found for zlib,
a required dependency when compiling Pillow from source.

Please see the install instructions at:
https://pillow.readthedocs.io/en/latest/installation.html

Traceback (most recent call last):
File "/private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-install-gtdo_7kf/Pillow/setup.py", line 760, in
setup(name=NAME,
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/setuptools/__init__.py", line 145, in setup
return distutils.core.setup(**attrs)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/core.py", line 148, in setup
dist.run_commands()
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/dist.py", line 966, in run_commands
self.run_command(cmd)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/dist.py", line 985, in run_command
cmd_obj.run()
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/setuptools/command/install.py", line 61, in run
return orig.install.run(self)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/command/install.py", line 545, in run
self.run_command('build')
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/cmd.py", line 313, in run_command
self.distribution.run_command(command)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/dist.py", line 985, in run_command
cmd_obj.run()
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/command/build.py", line 135, in run
self.run_command(cmd_name)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/cmd.py", line 313, in run_command
self.distribution.run_command(command)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/dist.py", line 985, in run_command
cmd_obj.run()
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/distutils/command/build_ext.py", line 340, in run
self.build_extensions()
File "/private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-install-gtdo_7kf/Pillow/setup.py", line 582, in build_extensions
raise RequiredDependencyException(f)
__main__.RequiredDependencyException: zlib

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "", line 1, in
File "/private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-install-gtdo_7kf/Pillow/setup.py", line 807, in
raise RequiredDependencyException(msg)
__main__.RequiredDependencyException:

The headers or library files could not be found for zlib,
a required dependency when compiling Pillow from source.

Please see the install instructions at:
https://pillow.readthedocs.io/en/latest/installation.html


----------------------------------------
ERROR: Command errored out with exit status 1: /Library/Frameworks/Python.framework/Versions/3.8/bin/python3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-install-gtdo_7kf/Pillow/setup.py'"'"'; __file__='"'"'/private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-install-gtdo_7kf/Pillow/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /private/var/folders/k_/lhglds3j0k52fgg96l4r62lm0000gn/T/pip-record-kif646zv/install-record.txt --single-version-externally-managed --compile Check the logs for full command output.

From the requirements.txt file, I removed the equals sign and the numbers on the line "opencv-python==3.4.2.17" as I had an error that's similar to what's detailed here: [https://github.com/3b1b/manim/issues/773](https://github.com/3b1b/manim/issues/773)

This fixed that particular error, but then I got two more errors. One is in regards to the large error message detailed above, and the other one was "opencv-python 4.2.0.32 has requirement numpy>=1.17.3, but you'll have numpy 1.15.0 which is incompatible." I updated my version of numpy and that didn't work, so I changed the line in requirements.txt to be "numpy==1.18.1" (updated version). So that error is now gone but the error above persists.

Any help on how to resolve this error would be greatly appreciated.