Add API checking using clirr

In order to generate API reports run: mvn clirr:clirr

The reports are generated to the folder
target/site/clirr-report.html under the respective
project.

In order to check API compatibility and fail the build
on incompatible changes run: mvn clirr:check

For now we compare the API against the latest release
1.1.0.201109151100-r.

Bug: 336849
Change-Id: I21baaf3a6883c5b4db263f712705cc7b8ab6d888
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Kevin Sawicki <kevin@github.com>
diff --git a/org.eclipse.jgit/pom.xml b/org.eclipse.jgit/pom.xml
index 97e08f6..33e972e 100644
--- a/org.eclipse.jgit/pom.xml
+++ b/org.eclipse.jgit/pom.xml
@@ -142,7 +142,13 @@
           </archive>
         </configuration>
       </plugin>
+
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>clirr-maven-plugin</artifactId>
+      </plugin>
     </plugins>
+
     <pluginManagement>
       <plugins>
         <plugin>
@@ -155,4 +161,18 @@
       </plugins>
     </pluginManagement>
   </build>
+
+  <reporting>
+    <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>clirr-maven-plugin</artifactId>
+        <version>${clirr-version}</version>
+        <configuration>
+          <comparisonVersion>${jgit-last-release-version}</comparisonVersion>
+          <minSeverity>info</minSeverity>
+        </configuration>
+      </plugin>
+    </plugins>
+  </reporting>
 </project>