Explicitly initialize COM library in main and opengl threads, hopefully fixing filedialog issues.

src/win/win.c

@@ -417,6 +417,9 @@ WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR lpszArg, int nCmdShow)
 
     SetCurrentProcessExplicitAppUserModelID(AppID);
 
+    /* Initialize the COM library for the main thread. */
+    CoInitializeEx(NULL, COINIT_MULTITHREADED);
+
     /* Check if Windows supports UTF-8 */
     if (GetACP() == CP_UTF8)
 	acp_utf8 = 1;
@@ -465,6 +468,9 @@ WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR lpszArg, int nCmdShow)
     /* Handle our GUI. */
     i = ui_init(nCmdShow);
 
+    /* Uninitialize COM before exit. */
+    CoUninitialize();
+
     free(argbuf);
     free(argv);
     return(i);