[Bug 51899] 16-bit Collins Dictionary has black background.

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=51899

--- Comment #6 from Bruni  ---
My bad

According to PTHREAD specification, it does not guarantee that instructions
inside the lock itself are protected from reordering.

So, it's better to put multiple locks.

DC_ATTR *get_dc_attr( HDC hdc )
{
    pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;

pthread_mutex_lock( &lock );
    DWORD type = gdi_handle_type( hdc );
    DC_ATTR *dc_attr;
    pthread_mutex_unlock( &lock );

pthread_mutex_lock( &lock );
    unsigned int comparedType = type & 0x1f0000;
    pthread_mutex_unlock( &lock );

pthread_mutex_lock( &lock );
    unsigned int ntgdiObjDc = comparedType & NTGDI_OBJ_DC;
    pthread_mutex_unlock( &lock );

pthread_mutex_lock( &lock );
    dc_attr = get_gdi_client_ptr( hdc, 0 );
    pthread_mutex_unlock( &lock );

pthread_mutex_lock( &lock );
    if (!ntgdiObjDc)
    {
        SetLastError( ERROR_INVALID_HANDLE );
        return NULL;
    }
    pthread_mutex_unlock( &lock );

pthread_mutex_lock( &lock );
    if (!dc_attr)
    {
        SetLastError( ERROR_INVALID_HANDLE );
        return NULL;
    }
    pthread_mutex_unlock( &lock );
    return dc_attr->disabled ? NULL : dc_attr;
}