Can I modify winuser.h ?

[olivier]

Hello,
I try to use a win32 app that use the user32 function:
BOOL WINAPI FlashWindowEx(PFLASHWINFO pfwi )

the implemented function in Wine is:
BOOL WINAPI FlashWindow( HWND hWnd, BOOL bInvert)

My question, can I modify the user32.spec and the winuser.h to add this
function with?

BOOL WINAPI FlashWindowEx(PFLASHWINFO pfwi )

  /* FlashWindowEx structure and flags*/
typedef struct {
        UINT    cbSize;
        HWND    hwnd;
        DWORD   dwFlags;
        UINT    uCount;
        DWORD   dwTimeout;
} FLASHWINFO, *PFLASHWINFO;

#define FLASHW_STOP             0x01
#define FLASHW_CAPTION          0x02
#define FLASHW_TRAY             0x04
#define FLASHW_ALL              FLASHW_CAPTION | FLASHW_TRAY
#define FLASHW_TIMER            0x10
#define FLASHW_TIMERNOFG        0x20


And an other question. After modifying the user32.spec to rebuild, do I
just type make? 

Merci,
Olivier