Suggest git submodule init / update in README

[martinemde]

When I went to build this (after building skia) I had these errors that blocked the build:

CMake Error at CMakeLists.txt:62 (add_subdirectory):
  The source directory

   path/to/laf/clip

  does not contain a CMakeLists.txt file.


CMake Error at third_party/CMakeLists.txt:10 (add_subdirectory):
  The source directory

   path/to/laf/third_party/googletest

  does not contain a CMakeLists.txt file.

The solution is to init and update submodules after cloning.

git submodule update --init

This will fetch the correct files and allow you to build.

It would be nice to make sure others know to init and update submodules when they fetch the code. I rarely work in projects that have submodules so I didn't immediately realize this was simple to solve.

I agree that my contributions are licensed under the MIT License.
You can find a copy of this license at https://opensource.org/licenses/MIT

[dacap]

Thanks for this @martinemde, I've updated the instructions to use git clone --recursive which is the preferred method to initialize the repository.