Fix civetweb/civetweb#394: static_assert on Windows with Clang
Fix civetweb/civetweb#394: static_assert on Windows with Clang

GerHobbelt/civet-webserver,GerHobbelt/civet-webserver,GerHobbelt/civet-webserver,GerHobbelt/civet-webserver,GerHobbelt/civet-webserver,GerHobbelt/civet-webserver