Add failonerror to generate-task to stop build on error

debian/patches/fail_when_generate_fails.patch

+Index: netlib-java/build.xml
+===================================================================
+--- netlib-java.orig/build.xml
++++ netlib-java/build.xml
+@@ -25,7 +25,7 @@
+ 	</target>
+ 	<target name="generate" depends="compile">
+ 		<!-- Autogenerate the Java and C files -->
+-		<java fork="yes" classname="org.netlib.generate.JavaGenerator" classpath="${run.classpath}" />
++		<java fork="yes" classname="org.netlib.generate.JavaGenerator" classpath="${run.classpath}" failonerror="true"/>
+ 	</target>
+ 	
+ 	<!--

debian/patches/series

 update_classpath.patch
 set_source_1_8.patch
 URLClassLoader.patch
+fail_when_generate_fails.patch