change: don't compile syslog support by default
change: don't compile syslog support by default

this feature is still in experimental status, not ready for production.

Signed-off-by: paulyang <5909991d80aa1f224864e8a7fe6e5ae7399dfbc1@neusoft.com>

yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx,yeahdongcn/SEnginx