diff --git a/configure.ac b/configure.ac
index 9aa23ff0bf5..7e5e1711961 100644
--- a/configure.ac
+++ b/configure.ac
@@ -202,6 +202,15 @@ if test "x$enable_developer_docs" = xyes; then
 fi
 AM_CONDITIONAL(BUILD_DOCS, [test "x$enable_docs" = xyes])
 
+# Did the user specify an MPI launcher other than mpiexec?
+AC_MSG_CHECKING([whether a user specified program to run mpi programs])
+AC_ARG_WITH([mpiexec],
+              [AS_HELP_STRING([--with-mpiexec=<command>],
+                              [Specify command to launch MPI parallel tests.])],
+            [MPIEXEC=$with_mpiexec], [MPIEXEC=mpiexec])
+AC_MSG_RESULT([$MPIEXEC])
+AC_SUBST([MPIEXEC], [$MPIEXEC])
+
 # Is doxygen installed?
 AC_CHECK_PROGS([DOXYGEN], [doxygen])
 if test -z "$DOXYGEN" -a "x$enable_docs" = xyes; then
@@ -390,6 +399,9 @@ AM_CONDITIONAL(NETCDF_INTEGRATION, [test "x$enable_netcdf_integration" = xyes])
 
 AC_CONFIG_FILES([tests/general/pio_tutil.F90:tests/general/util/pio_tutil.F90])
 
+# The user may have changed the MPIEXEC for these test scripts.
+AC_CONFIG_FILES([tests/cunit/run_tests.sh], [chmod ugo+x h5_tests/cunit/run_tests.sh])
+
 # Args:
 # 1. netcdf_meta.h variable
 # 2. conditional variable that is yes or no.
diff --git a/tests/cunit/Makefile.am b/tests/cunit/Makefile.am
index 78bf18f24bb..7a8edd61941 100644
--- a/tests/cunit/Makefile.am
+++ b/tests/cunit/Makefile.am
@@ -69,7 +69,9 @@ test_async_1d_SOURCES = test_async_1d.c pio_tests.h
 test_simple_SOURCES = test_simple.c test_common.c pio_tests.h
 
 # Distribute the test script.
-EXTRA_DIST = run_tests.sh CMakeLists.txt test_darray_frame.c
+EXTRA_DIST = run_tests.sh.in CMakeLists.txt test_darray_frame.c
 
 # Clean up files produced during testing.
 CLEANFILES = *.nc *.log decomp*.txt *.clog2 *.slog2
+
+DISTCLEANFILES = run_tests.sh