Pillow 4.3 -> 5.3 upgrade between Plone 5.1.2 and 5.1.4 breaking installations on Debian 9

Plone 5.1.2 uses Pillow 4.3.0
Plone 5.1.4 uses Pillow 5.3.0

And this upgrade breaks the Pillow installation on Debian 9

unning 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 "setup.py", line 814, in <module>
    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

zlib1 is clearly installed:

root@plone:~# apt list --installed |grep zlib1

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

zlib1g/stable,now 1:1.2.8.dfsg-5 amd64 [installed]
zlib1g-dev/stable,now 1:1.2.8.dfsg-5 amd64 [installed]

While this is possibly a Pillow related issue, I wonder why Pillow was upgrade from one major release to another major release within a minor version update of Plone?

Plone 5.1.4 uses Pillow 5.2.0 which works fine (http://dist.plone.org/release/5.1-latest/versions.cfg)
Plone 5.2 uses Pillow 5.3.0 which has a bug as you've already commented (also on MacOS) ...

Pillow 5.X does not build correctly on Debian 9

ah, sorry ... missed that. Ubuntu is working.

Installing Pillow 5.3.0 works fine for me on Debian 9 after installing the build time dependencies via apt build-dep python-imaging.