mmdevapi: Use InitOnce to initialize audio drivers.

dlls/mmdevapi/main.c

@@ -109,7 +109,7 @@ static BOOL load_driver(const WCHAR *name, DriverFuncs *driver)
     return TRUE;
 }
 
-static BOOL init_driver(void)
+static BOOL WINAPI init_driver(INIT_ONCE *once, void *param, void **context)
 {
     static const WCHAR drv_value[] = {'A','u','d','i','o',0};
 
@@ -120,9 +120,6 @@ static BOOL init_driver(void)
     HKEY key;
     WCHAR reg_list[256], *p, *next, *driver_list = default_list;
 
-    if(drvs.module)
-        return TRUE;
-
     if(RegOpenKeyW(HKEY_CURRENT_USER, drv_keyW, &key) == ERROR_SUCCESS){
         DWORD size = sizeof(reg_list);
 
@@ -276,10 +273,11 @@ static IClassFactoryImpl MMDEVAPI_CF[] = {
 
 HRESULT WINAPI DllGetClassObject(REFCLSID rclsid, REFIID riid, LPVOID *ppv)
 {
+    static INIT_ONCE init_once = INIT_ONCE_STATIC_INIT;
     unsigned int i = 0;
     TRACE("(%s, %s, %p)\n", debugstr_guid(rclsid), debugstr_guid(riid), ppv);
 
-    if(!init_driver()){
+    if(!InitOnceExecuteOnce(&init_once, init_driver, NULL, NULL)) {
         ERR("Driver initialization failed\n");
         return E_FAIL;
     }