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/libavif/libavif.toml

@@ -0,0 +1,54 @@
+[build]
+type = "cmake"
+
+[build.flags]
+build_dir = "build"
+configure = [
+    "-DAVIF_BUILD_MAN_PAGES=ON",
+    "-DAVIF_BUILD_APPS=ON",
+    "-G Ninja",
+    "-DAVIF_CODEC_AOM=SYSTEM",
+    "-DAVIF_CODEC_DAV1D=SYSTEM",
+    "-DAVIF_CODEC_RAV1E=SYSTEM",
+    "-DAVIF_CODEC_SVT=SYSTEM",
+    "-DAVIF_LIBSHARPYUV=SYSTEM",
+    "-DAVIF_LIBXML2=SYSTEM",
+    "-DAVIF_BUILD_GDK_PIXBUF=OFF",
+]
+
+[dependencies]
+build = [
+    "cmake",
+    "ninja",
+    "nasm",
+    "pandoc",
+]
+runtime = [
+    "aom",
+    "dav1d",
+    "glibc",
+    "libunwind",
+    "libjpeg-turbo",
+    "libpng",
+    "libcxx",
+    "libwebp",
+    "libxml215",
+    "libyuv",
+    "rav1e",
+    "svt-av1",
+]
+
+[[manual_sources]]
+url = "https://github.com/kmurray/libargparse.git#ee74d1b53bd680748af14e737378de57e2a0a954"
+
+[package]
+description = "Library for encoding and decoding .avif files"
+homepage = "https://github.com/AOMediaCodec/libavif"
+license = "LicenseRef-libavif"
+name = "libavif"
+version = "1.4.1"
+
+[[source]]
+extract_dir = "$name-$version"
+post_extract = ["pkg-config --cflags --libs libsharpyuv", "cp -r ../libargparse ./ext"]
+url = "https://github.com/AOMediaCodec/libavif#v$version"