cosmetic msvc xml fix
selftest/zauth: increase poll timeout for slow platforms

fixes #497 .
Merge pull request #499 from mhaberler/master

selftest/zauth: increase poll timeout for slow platforms
Merge pull request #498 from hintjens/master

Problem: under some debuggers, asserts in zsys_close
Merge pull request #500 from evoskuil/master

cosmetic msvc xml fix
On 64-bit Windows, ssize_t is long long

Fixes #502