minor docs updates

[incanus]

1. iOS docs bug reported via user.
2. Update dependencies for CMake since Switch build system to CMake #5359 landed. (look ok @kkaefer?)

[mention-bot]

@incanus, thanks for your PR! By analyzing this pull request, we identified @1ec5, @tmcw and @friedbunny to be potential reviewers.

[1ec5]

👍

[kkaefer]

We don't need python anymore afaik.

[friedbunny]

It would also be great to verify that the test instructions still work and are accurate.

[mikemorris]

It appears that we specifically require CMake v3.x+, which on Ubuntu 12.04 requires adding a backport ppa (discovered this by digging around in .travis.yml):

sudo apt-add-repository ppa:george-edison55/precise-backports
sudo apt-get update

Attempting to install with CMake 2.8.7 yields the following error:

(cd build/linux-x86_64/Debug && cmake -G Ninja ../../.. \
                -DCMAKE_BUILD_TYPE=Debug \
                -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
                -DWITH_CXX11ABI=OFF \
                -DWITH_COVERAGE=)
CMake Error: Could not create named generator Ninja
make: *** [build/linux-x86_64/Debug/build.ninja] Error 1

[mikemorris]

It appears that we're no longer using pkg-config either? Oops, looks like we're using it indirectly via find_package in CMake now

I was previously using this to ensure we were compiling and linking against a mason-installed version of Mesa, ran into trouble rebasing 04fc3cb onto master because now it can't find EGL/egl.h (which it previously found through pkg-config --cflags)

[kkaefer]

We are not using find_package in CMake. However, we are using it indirectly because we are invoking mason (which could call pkg-config based on the script.sh) when there is no mason.ini file yet in the package. As we move on and more of the packages we use contain a mason.ini in the precompiled tarball download, we can remove the on-demand mason.ini creation, which removes the pkg-config requirement for Mapbox GL Native.

For what it's worth, we only require Python for creating the shader files and version headers, but we can easily move this to node.js, which we require anyway because of our use of npm.

[kkaefer]

created ticket for Python removal: #6010

[kkaefer]

Yes, we require CMake 3.1 due to features we used that are not present before 3.1.

[1ec5]

@bleege committed the CMake change directly to master in bbd6cfc.

[bleege]

I rebased the development branch onto master and then added an update to explicitly say CMake 3.1 or later per @kkaefer's note. Once CI 👍 I'll merge this into master.

[bleege]

CI Tested and Approved. We're documented once again!