docs: mention apt-get for manylinux2_24 (#623)

* mention apt-get for manylinux2_24

* Fix typo

* Undo reflow; pushing to a potentially separate PR

Co-authored-by: Yannick Jadoul <yannick.jadoul@belgacom.net>

docs/faq.md

@@ -18,7 +18,7 @@ If your wheel didn't compile, check the list below for some debugging tips.
 
 Linux wheels are built in the [`manylinux` docker images](https://github.com/pypa/manylinux) to provide binary compatible wheels on Linux, according to [PEP 571](https://www.python.org/dev/peps/pep-0571/). Because of this, when building with `cibuildwheel` on Linux, a few things should be taken into account:
 
-- Programs and libraries cannot be installed on the Travis CI Ubuntu host with `apt-get`, but can be installed inside of the Docker image using `yum` or manually. The same goes for environment variables that are potentially needed to customize the wheel building. `cibuildwheel` supports this by providing the `CIBW_ENVIRONMENT` and `CIBW_BEFORE_BUILD` options to setup the build environment inside the running Docker image. See [the options docs](options.md#build-environment) for details on these options.
+- Programs and libraries are not installed on the Travis CI Ubuntu host, but rather should be installed inside of the Docker image (using `yum` for `manylinux2010` or `manylinux2014`, and `apt-get` for `manylinux_2_24`) or manually. The same goes for environment variables that are potentially needed to customize the wheel building. `cibuildwheel` supports this by providing the `CIBW_ENVIRONMENT` and `CIBW_BEFORE_BUILD` options to setup the build environment inside the running Docker image. See [the options docs](options.md#build-environment) for details on these options.
 
 - The project directory is mounted in the running Docker instance as `/project`, the output directory for the wheels as `/output`. In general, this is handled transparently by `cibuildwheel`. For a more finegrained level of control however, the root of the host file system is mounted as `/host`, allowing for example to access shared files, caches, etc. on the host file system.  Note that this is not available on CircleCI due to their Docker policies.
 

docs/options.md

@@ -354,6 +354,11 @@ CIBW_BEFORE_ALL: make -C third_party_lib
 CIBW_BEFORE_ALL_LINUX: yum install -y libffi-dev
 ```
 
+Note that manylinux2_24 builds occur inside a Debian9 docker, where
+manylinux2010 and manylinux2014 builds occur inside a CentOS one. So for
+`manylinux2_24` the `CIBW_BEFORE_ALL_LINUX` command must use `apt-get -y`
+instead.
+
 ### `CIBW_BEFORE_BUILD` {: #before-build}
 > Execute a shell command preparing each wheel's build