cmake: do not use stderr for notifications/version-info For all except "STATUS" message() will write to stderr, and this also includes case when you does not have <mode> at all. Plus for every message in stderr powershell generates exception and make appveyor fails. Fixes: https://ci.appveyor.com/project/azat/libevent/build/2.1.5.85/job/i10k7m0t80330mtr