server: Avoid sending unexpected wakeup with uninitialized cookie value.

[Sebastian Lackner]

While executing the kernel32/sync tests I noticed a couple of unexpected wakeup cookies, which looked like uninitialized wineserver memory.
Here an excerpt from the log (added additional debug values):

--- snip ---
0009: select( flags=2, cookie=0033faac, timeout=0, prev_apc=0000, result={}, data={SIGNAL_AND_WAIT,signal=0038,wait=0038} )
0009: *wakeup* signaled=0 cookie=0x55555555
0009: select() = 0 { timeout=1d00663fadcfb0a (+0.0000000), call={APC_NONE}, apc_handle=0000 }
[...]
0009: select( flags=2, cookie=0033faac, timeout=0, prev_apc=0000, result={}, data={SIGNAL_AND_WAIT,signal=0038,wait=0038} )
0009: *wakeup* signaled=0 cookie=0x55555555
0009: select() = 0 { timeout=1d00663fadcfdf8 (+0.0000000), call={APC_NONE}, apc_handle=0000 }
[...]
0009: select( flags=2, cookie=0033f8dc, timeout=+0.0100000, prev_apc=0000, result={}, data={WAIT,handles={0038}} )
0009: select() = PENDING { timeout=1d00663fae61280 (+0.0100000), call={APC_NONE}, apc_handle=0000 }
0009:fixme:server:wait_select_reply cookie = 0x55555555
0009:fixme:server:wait_select_reply cookie = 0x55555555
--- snip ---

Those unexpected wakeup cookies are never removed again, and could overflow the wakeup pipe sooner or later.

The problem is caused when signalling and waiting on the same object. wait_on_handles(...) allocates the current->wait structure, but doesn't store a cookie yet. Afterwards the object is signalled, and wake_thread(...) is executed, which sends a wakeup cookie. This normally isn't necessary because we're still in the same wine server call, and the thread isn't waiting for any reply.

---
 server/thread.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
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