test for full CCTK_PointerTo code in configure

[Roland Haas]

To support gfortran 10 some changes were introduced to CCTK_PointerTo and key functionality was tested for in configure.

However some old gfortran compilers (4.8) support just enough syntax to make the configure test pass but CCTK_PointerTo fail. See #2455. Unfortunately this old compiler is the default of redhat 7.

The patch in https://bitbucket.org/cactuscode/cactus/pull-requests/109/cactus-test-full-cctk_pointerto-function makes configure test for the full CCTK_PointerTo code instead.

[Roland Haas]

Please review.

[Roland Haas]

Unless objected I will apply this after 2020-10-4.

[Erik Schnetter]

Please apply.

[Roland Haas]

Applied as git hash 08565e42 "Cactus: regenerate configure" of cactus

[Roland Haas]

Thank you.