[MPOM-255] Enforce local property "project.build.outputTimestamp" for reproducible builds (2)

This closes #33
diff --git a/.maven-apache-parent.marker b/.maven-apache-parent.marker
new file mode 100644
index 0000000..864fd14
--- /dev/null
+++ b/.maven-apache-parent.marker
@@ -0,0 +1,17 @@
+<!---
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements.  See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ (the "License"); you may not use this file except in compliance with
+ the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+This is just a marker file to make sure that profile "enforce-output-timestamp-property" is not active for builds of this project.
diff --git a/pom.xml b/pom.xml
index d0ee211..6cd826e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -323,7 +323,7 @@
         <artifactId>maven-enforcer-plugin</artifactId>
         <executions>
           <execution>
-            <id>enforce-maven-version-and-timestamp-property</id>
+            <id>enforce-maven-version</id>
             <goals>
               <goal>enforce</goal>
             </goals>
@@ -332,10 +332,6 @@
                 <requireMavenVersion>
                   <version>3.1.1</version>
                 </requireMavenVersion>
-                <requireProperty>
-                  <property>project.build.outputTimestamp</property>
-                  <message>The property "project.build.outputTimestamp" must be set on the reactor's root pom.xml to make the build reproducible. Further information at "https://maven.apache.org/guides/mini/guide-reproducible-builds.html".</message>
-                </requireProperty>
               </rules>
             </configuration>
           </execution>
@@ -472,5 +468,37 @@
       </build>
     </profile>
     <!-- END SNIPPET: release-profile -->
+    <profile>
+      <id>enforce-output-timestamp-property</id>
+      <activation>
+        <file>
+          <missing>${basedir}/.maven-apache-parent.marker</missing>
+        </file>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-enforcer-plugin</artifactId>
+            <executions>
+              <execution>
+                <id>enforce-output-timestamp-property</id>
+                <goals>
+                  <goal>enforce</goal>
+                </goals>
+                <configuration>
+                  <rules>
+                    <requireProperty>
+                      <property>project.build.outputTimestamp</property>
+                      <message>The property "project.build.outputTimestamp" must be set on the reactor's root pom.xml to make the build reproducible. Further information at "https://maven.apache.org/guides/mini/guide-reproducible-builds.html".</message>
+                    </requireProperty>
+                  </rules>
+                </configuration>
+              </execution>
+            </executions>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
   </profiles>
 </project>