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

[WineHQ Bugzilla]

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

--- Comment #5 from Bruni  ---
Try to forbid a compiler to reorder instructions using mutex locks (by
inserting memory barriers) with something like

...
#include <pthread.h>
...

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;
    if ((type & 0x1f0000) != NTGDI_OBJ_DC || !(dc_attr = get_gdi_client_ptr(
hdc, 0 )))
    {
        SetLastError( ERROR_INVALID_HANDLE );
        return NULL;
    }
    pthread_mutex_unlock( &lock );
    return dc_attr->disabled ? NULL : dc_attr;
}