Make 'test_cksum_base' responsible for skipping tests.

.gitignore

configure.ac

tests/Makefile.am

tests/test_cksum_base

tests/test_cksum_base.in

tests/test_cksum_ext.run.in

tests/test_cksum_extra.run.in

tests/test_cksum_grb.run.in

tests/test_cksum_grb2.run.in

tests/test_cksum_grib2.run.in

tests/test_cksum_ieg.run.in

tests/test_cksum_nc.run.in

tests/test_cksum_nc2.run.in

tests/test_cksum_nc4.run.in

tests/test_cksum_service.run.in

tests/test_cksum_srv.run.in