cmake SYSLOG_NG_HAVE_PAHO_HTTP_PROXY examples

syslog-ng/syslog-ng modules/mqtt/CMakeLists.txt :15 

CHECK_STRUCT_HAS_MEMBER("MQTTClient_connectOptions" "httpProxy" "MQTTClient.h" SYSLOG_NG_HAVE_PAHO_HTTP_PROXY)