Add "Build System" section to godot-cpp docs (SCons and CMake).

tutorials/scripting/cpp/build_system/scons.rst

@@ -0,0 +1,75 @@
+.. _doc_godot_cpp_build_system:
+
+Main build system: Working with SCons
+=====================================
+
+.. seealso:: This page documents how to compile godot-cpp. If you're looking to compile Godot instead, see
+             :ref:`doc_introduction_to_the_buildsystem`.
+
+`godot-cpp <https://github.com/godotengine/godot-cpp>`__ uses `SCons <https://scons.org>`__ as its main build system.
+It is modeled after :ref:`Godot's build system <doc_compiling_index>`, and some commands available there are also
+available in godot-cpp projects.
+
+Getting started
+---------------
+
+To build a godot-cpp project, it is generally sufficient to install `SCons <https://scons.org>`__, and simply run it
+in the project directory:
+
+    scons
+
+You may want to learn about available options:
+
+    scons --help
+
+To cleanly re-build your project, add ``--clean`` to your build command:
+
+    scons --clean
+
+You can find more information about common SCons arguments and build patterns in the
+`SCons User Guide <https://scons.org/doc/latest/HTML/scons-user/index.html>`__. Additional commands may be added by
+individual godot-cpp projects, so consult their specific documentation for more information on those.
+
+Configuring an IDE
+------------------
+
+Most IDEs can use a ``compile_commands.json`` file to understand a C++ project. You can generate it with godot-cpp using
+the following command:
+
+.. code-block:: shell
+
+   # Generate compile_commands.json while compiling.
+   scons compiledb=yes
+
+   # Generate compile_commands.json without compiling.
+   scons compiledb=yes compile_commands.json
+
+For more information, please check out the :ref:`IDE configuration guides <doc_configuring_an_ide>`.
+Although written for Godot engine contributors, they are largely applicable to godot-cpp projects as well.
+
+Loading your GDExtension in Godot
+---------------------------------
+
+Godot loads GDExtensions by finding :ref:`.gdextension <doc_gdextension_file>` files in the project directory.
+``.gdextension`` files are used to select and load a binary compatible with the current computer / operating system.
+
+The `godot-cpp-template <https://github.com/godotengine/godot-cpp-template>`__, as well as the
+:ref:`Getting Started section <doc_godot_cpp_getting_started>`, provide example ``.gdextension`` files for GDExtensions
+that are widely compatible to many different systems.
+
+Building for multiple platforms
+-------------------------------
+
+GDExtensions are expected to run on many different systems, each with separate binaries and build configurations.
+If you are planning to publish your GDExtension, we recommend you provide binaries for all configurations that are
+mentioned in the `godot-cpp-template <https://github.com/godotengine/godot-cpp-template>`__
+`.gdextension file <https://github.com/godotengine/godot-cpp-template/blob/main/demo/bin/example.gdextension>`__.
+
+There are two popular ways by which cross platform builds can be achieved:
+
+- Cross-platform build tools
+- Continuous Integration (CI)
+
+`godot-cpp-template <https://github.com/godotengine/godot-cpp-template>`__ contains an
+`example setup <https://github.com/godotengine/godot-cpp-template/tree/main/.github/workflows>`__
+for a GitHub based CI workflow.