Make various updates and fixes:

- Add support for legacy CUDA versions; now compatible with CUDA 12.3 and newer
- Add support for NVRTC compilation
- Other fixes and code refactoring

csrc/utils/lazy_init.hpp

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <functional>
+#include <memory>
+
+#define DG_DECLARE_STATIC_VAR_IN_CLASS(cls, name) decltype(cls::name) cls::name
+
+namespace deep_gemm {
+
+template <typename T>
+class LazyInit {
+public:
+    explicit LazyInit(std::function<std::shared_ptr<T>()> factory)
+        : factory(std::move(factory)) {}
+
+    T* operator -> () {
+        if (ptr == nullptr)
+            ptr = factory();
+        return ptr.get();
+    }
+
+private:
+    std::shared_ptr<T> ptr;
+    std::function<std::shared_ptr<T>()> factory;
+};
+
+} // namespace deep_gemm