no exit when executing 'mvn --fail-at-end'

Makefile

@@ -8,8 +8,8 @@ doc:
 	cd Doc;$(MAKE) -j${numCores} all
 
 all:doc
-	mvn --fail-at-end install 
-	mvn -T ${numCores} --fail-at-end javadoc:javadoc
+	mvn --fail-at-end install || exit 0
+	mvn -T ${numCores} --fail-at-end javadoc:javadoc || exit 0
 	mkdir -p Doc/target/navi/de.hdm_stuttgart.mi.lectures/P
 	cd P;$(MAKE) -j ${numCores} install
 	cd P; tar c- ${DOCMODULES} | tar -x -C ../Doc/target/navi/de.hdm_stuttgart.mi.lectures/P