Added Build Rule
Added Build Rule

Add build rule, to only build on Linux platform, reason for adding this: This allows the usage of the logrus package within a Windows based project. Current logrus project fails to import due to the fact the syslog is missing on Windows.
penhauer-xiao/logrus,freeformz/logrus,sirupsen/logrus,Sirupsen/logrus,akutz/logrus,sirupsen/logrus,yxd-hde/logrus,axiomzen/logrus,devopstaku/logrus,penhauer-xiao/logrus