ntdll: Only grab the loader lock once we actually call external functions.

dlls/ntdll/loader.c

@@ -2340,8 +2340,6 @@ void WINAPI LdrInitializeThunk( ULONG unknown1, ULONG unknown2, ULONG unknown3,
     status = server_init_process_done();
     if (status != STATUS_SUCCESS) goto error;
 
-    RtlEnterCriticalSection( &loader_section );
-
     actctx_init();
     load_path = NtCurrentTeb()->Peb->ProcessParameters->DllPath.Buffer;
     if ((status = fixup_imports( wm, load_path )) != STATUS_SUCCESS) goto error;
@@ -2350,6 +2348,8 @@ void WINAPI LdrInitializeThunk( ULONG unknown1, ULONG unknown2, ULONG unknown3,
 
     pthread_functions.sigprocmask( SIG_UNBLOCK, &server_block_set, NULL );
 
+    RtlEnterCriticalSection( &loader_section );
+
     if ((status = process_attach( wm, (LPVOID)1 )) != STATUS_SUCCESS)
     {
         if (last_failed_modref)