Only set CMAKE_BUILD_TYPE on supported generators
Only set CMAKE_BUILD_TYPE on supported generators

CMAKE_BUILD_TYPE only works with Ninja and Makefile based projects.
This we should only set it when we're using that kind of Generator.
Also print out a status message if a default is set

sakishum/rabbitmq-c,soindy/rabbitmq-c,chenwenbin928/rabbitmq-c,kilinrax/rabbitmq-c,jqk6/rabbitmq-c,hjzljp/rabbitmq-c,jasonmsoft/rabbitmq-c,chenwenbin928/rabbitmq-c,hjzljp/rabbitmq-c,jasonmsoft/rabbitmq-c,tempbottle/rabbitmq-c,hjzljp/rabbitmq-c,alanxz/rabbitmq-c,soindy/rabbitmq-c,Haster2004/rabbitmq-c,sakishum/rabbitmq-c,soindy/rabbitmq-c,Haster2004/rabbitmq-c,jqk6/rabbitmq-c,jasonmsoft/rabbitmq-c,tempbottle/rabbitmq-c,alanxz/rabbitmq-c,alanxz/rabbitmq-c,sakishum/rabbitmq-c,Haster2004/rabbitmq-c,jasonmsoft/rabbitmq-c,kilinrax/rabbitmq-c,tempbottle/rabbitmq-c,jqk6/rabbitmq-c,jqk6/rabbitmq-c,tempbottle/rabbitmq-c,chenwenbin928/rabbitmq-c,kilinrax/rabbitmq-c,hjzljp/rabbitmq-c