cmake/win32: fix running regress, but fixing finding python2 interpreter Could not find executable C:/projects/libevent/build/bin/regress Looked in the following places: C:/projects/libevent/build/bin/regress C:/projects/libevent/build/bin/regress.exe ... 9/13 Test #9: regress__WIN32_debug ................***Not Run 0.00 sec Link: https://ci.appveyor.com/project/nmathewson/libevent/build/2.1.6.271/job/wvy2jp7uojcut5cx#L1256 Fixes: #411