Add configuration files and patches for R, SDL2, SDL3, Tk, and Vala

- Introduced `r.toml` for R package configuration, including build flags and dependencies.
- Added `sdl2-compat.toml` for SDL2 compatibility layer with SDL3, specifying build and runtime dependencies.
- Created a patch for SDL3 to handle cases when XInput2 is not available, ensuring compatibility.
- Added `sdl3.toml` for SDL3 configuration, including build flags and dependencies.
- Introduced `tk.toml` for Tk configuration, detailing build flags and runtime dependencies.
- Added a patch for Vala to ensure POSIX compliance in the test runner script, improving portability.

extra/python-sphinx-copybutton/python-sphinx-copybutton.toml

@@ -0,0 +1,18 @@
+[build]
+type = "python"
+
+[dependencies]
+build = ["python-setuptools"]
+runtime = ["python-sphinx"]
+
+[package]
+description = 'Sphinx extension to add a "copy" button to code blocks'
+homepage = "https://github.com/executablebooks/sphinx-copybutton"
+license = "MIT"
+name = "python-sphinx-copybutton"
+version = "0.5.2"
+
+[[source]]
+extract_dir = "$name-$version"
+sha256 = "4cf17c82fb9646d1bc9ca92ac280813a3b605d8c421225fd9913154103ee1fbd"
+url = "https://files.pythonhosted.org/packages/source/s/sphinx-copybutton/sphinx-copybutton-$version.tar.gz"