ARTEMIS-4153 Support 'offline' Maven

docs/hacking-guide/en/building.md

@@ -72,4 +72,9 @@ simply run
 
 ## Building the docs
 
-From either `docs/hacking-guide/en` or `docs/user-manual/en` run `gitbook build` (after you've installed gitbook)
+From either `docs/hacking-guide/en` or `docs/user-manual/en` run `gitbook build` (after you've installed gitbook)
+
+## Building offline
+
+    $ mvn dependency:go-offline
+    $ mvn -o ...

pom.xml

@@ -1479,6 +1479,15 @@
    </profiles>
 
    <build>
+      <extensions>
+         <!-- Generate os.detected.classifier property for Netty native dependencies -->
+         <extension>
+            <groupId>kr.motd.maven</groupId>
+            <artifactId>os-maven-plugin</artifactId>
+            <version>1.7.1</version>
+         </extension>
+      </extensions>
+
       <pluginManagement>
          <plugins>
          <plugin>