+--- a/tests/BD_Shape/Makefile.am
++++ b/tests/BD_Shape/Makefile.am
+@@ -21,8 +21,6 @@
+ # For the most up-to-date information see the Parma Polyhedra Library
+ # site: http://bugseng.com/products/ppl/ .
+
+-AUTOMAKE_OPTIONS = serial-tests
+-
+ if VALGRIND_TESTS_ENABLED
+
+ CHECKER = \
+--- a/tests/Box/Makefile.am
++++ b/tests/Box/Makefile.am
+@@ -21,8 +21,6 @@
+ # For the most up-to-date information see the Parma Polyhedra Library
+ # site: http://bugseng.com/products/ppl/ .
+
+-AUTOMAKE_OPTIONS = serial-tests
+-
+ if VALGRIND_TESTS_ENABLED
+
+ CHECKER = \
+--- a/tests/Concrete_Expression/Makefile.am
++++ b/tests/Concrete_Expression/Makefile.am
+@@ -21,8 +21,6 @@
+ # For the most up-to-date information see the Parma Polyhedra Library
+ # site: http://bugseng.com/products/ppl/ .
+
+-AUTOMAKE_OPTIONS = serial-tests
+-
+ if VALGRIND_TESTS_ENABLED
+
+ CHECKER = \
+--- a/tests/Octagonal_Shape/Makefile.am
++++ b/tests/Octagonal_Shape/Makefile.am
+@@ -21,8 +21,6 @@
+ # For the most up-to-date information see the Parma Polyhedra Library
+ # site: http://bugseng.com/products/ppl/ .
+
+-AUTOMAKE_OPTIONS = serial-tests
+-
+ if VALGRIND_TESTS_ENABLED
+
+ CHECKER = \