Add path to find llama.dll for MAUI

This commit is originally made by lcarrere in #180 .

I have confirmed this modification is OK in my windows 11 laptop, add make this commit according require of AsakusaRinne.

Author: evolcano

LLama/Native/NativeApi.Load.cs

@@ -74,6 +74,15 @@ private static int GetCudaMajorVersion()
                 {
                     return -1;
                 }
+
+                //Ensuring cuda bin path is reachable. Especially for MAUI environment.
+                string cudaBinPath = Path.Combine(cudaPath, "bin");
+
+                if (Directory.Exists(cudaBinPath))
+                {
+                    AddDllDirectory(cudaBinPath);
+                }
+
                 version = GetCudaVersionFromPath(cudaPath);
             }
             else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))

LLama/Native/NativeApi.cs

@@ -26,6 +26,9 @@ public static void llama_empty_call()
             llama_max_devices();
         }
 
+        [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
+        private static extern int AddDllDirectory(string NewDirectory);
+
         /// <summary>
         /// Get the maximum number of devices supported by llama.cpp
         /// </summary>