add from giga-device, new branch added

StgSharp.Native/sn-src/dllmain.c

@@ -0,0 +1,35 @@
+
+#include "StgSharpNative.h"
+
+#ifdef _WIN32
+
+// clang-format off
+
+BOOL APIENTRY DllMain(
+        HMODULE hModule,
+        DWORD  ul_reason_for_call,
+        LPVOID lpReserved
+)
+{
+        switch (ul_reason_for_call)
+        {
+        case DLL_PROCESS_ATTACH:
+                return 1;
+        case DLL_THREAD_ATTACH:
+                return 1;
+        case DLL_THREAD_DETACH:
+                return 1;
+        case DLL_PROCESS_DETACH:
+                return 1;
+        break;
+        }
+    return TRUE;
+}
+#else
+attribute((constructor)) void DllMain()
+{
+}
+
+#endif // _WIN32
+
+// clang-format on