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/sdl3/sdl3.toml

@@ -0,0 +1,59 @@
+[build]
+type = "cmake"
+
+[build.flags]
+build_dir = "build"
+configure = [
+    "-DSDL_STATIC=OFF",
+    "-G Ninja",
+    "-DSDL_RPATH=OFF",
+    "-DSDL_X11_XINPUT=OFF",
+    "-DSDL_X11_XFIXES=OFF",
+    "-DSDL_X11_XTEST=OFF",
+    "-DSDL_X11_XINPUT=OFF",
+]
+no-delete-static = true
+
+[dependencies]
+build = [
+    "cmake",
+    "ninja",
+    "wayland-protocols",
+    "mesa",
+    "alsa-lib",
+    "libxrandr",
+    "libxinerama",
+    "wayland",
+    "libxss",
+    "vulkan-headers",
+]
+optional = [
+    "alsa-lib",
+    "vulkan-driver",
+]
+runtime = [
+    "glibc",
+    "libxext",
+    "libx11",
+    "libgl",
+    "libxrender",
+    "libxcursor",
+    "hidapi",
+    "libusb",
+]
+
+[package]
+description = "A library for portable low-level access to a video framebuffer, audio output, mouse, and keyboard (Version 3)"
+homepage = "https://www.libsdl.org/"
+license = "Zlib"
+name = "sdl3"
+version = "3.4.2"
+
+[[manual_sources]]
+file = "sdl-libxinput.patch"
+
+[[source]]
+extract_dir = "$name-$version"
+sha256 = "ef39a2e3f9a8a78296c40da701967dd1b0d0d6e267e483863ce70f8a03b4050c"
+url = "https://github.com/libsdl-org/SDL/releases/download/release-$version/SDL3-$version.tar.gz"
+patches = [ "sdl-libxinput.patch" ]