This test does A LOT of *wakeup() calls and then calls curl_multi_poll()
twice. The first *poll() is then expected to return early and the second
not - as the first is supposed to drain the socketpair pipe.
It turns out however that when given "excessive" amounts of writes to
the pipe, some operating systems (the Solaris based are known) will
return EAGAIN before the pipe is drained, which in our test case causes
the second *poll() call to also abort early.
This change attempts to avoid the OS-specific behaviors in the test by
reducing the amount of wakeup calls from 1234567 to 10.
Reported-by: Andy Fiddaman
Fixes#5037Closes#5058
This commit adds curl_multi_wakeup() which was previously in the TODO
list under the curl_multi_unblock name.
On some platforms and with some configurations this feature might not be
available or can fail, in these cases a new error code
(CURLM_WAKEUP_FAILURE) is returned from curl_multi_wakeup().
Fixes#4418Closes#4608
