Add SCons variant_dir support #153

Job	Run time
📊 Static Checks / Format (clang-format, ruff format, file format)	12s
🛠️ Continuous Integration / 🐧 Build (Linux, GCC, CMake Ninja)	22m 12s
🛠️ Continuous Integration / 🐧 Linux (GCC)	43m 46s
🛠️ Continuous Integration / 🏁 Build (Windows, MSVC, CMake)	24m 48s
🛠️ Continuous Integration / 🐧 Linux (GCC, Double Precision)	43m 59s
🛠️ Continuous Integration / 🏁 Windows (x86_64, MSVC)	44m 51s
🛠️ Continuous Integration / 🏁 Windows (x86_64, MinGW)	3h 9m 6s
🛠️ Continuous Integration / 🍎 macOS (universal)	35m 16s
🛠️ Continuous Integration / 🤖 Android (arm64)	32m 14s
🛠️ Continuous Integration / 🍏 iOS (arm64)	22m 21s
🛠️ Continuous Integration / 🌐 Web (wasm32)	57m 56s
	8h 36m 41s

Provide feedback