add test maintainr-clean

ax_init_standard_project.m4

@@ -166,6 +166,13 @@ AC_DEFUN([AX_USE_CPPUNIT], [
      - you cannot check the library using "make check"
      - everything else works perfectly]); fi
   AC_CONFIG_FILES([test/makefile])
+  AX_ADD_MAKEFILE_TARGET_DEP([maintainer-clean-am], [maintainer-clean-test-targets], [test/makefile.in])
+  test -f test/makefile.in && cat >> test/makefile.in <<EOF
+#### Begin: Appended by $0
+maintainer-clean-test-targets:
+	-rm makefile.in
+#### End: $0
+EOF
 ])
 
 AC_DEFUN([AX_BUILD_EXAMPLES], [