cpp version increase for CoDiPack

[MaxSagebaum]

Proposed Changes

Change the basic cpp version of SU2 to Cpp17 for CoDiPack v3.

Related Work

For the next release of CoDiPack we want to change the Cpp version of CoDiPack to Cpp17.

Other options

I tried not to change the global cpp version of SU2, but all attempts did not work.

• Using override options for the SU2_CFD_AD exec. Meson still used cpp11

diff --git a/SU2_CFD/src/meson.build b/SU2_CFD/src/meson.build
index 3b40822a34..a7246bcbf1 100644
--- a/SU2_CFD/src/meson.build
+++ b/SU2_CFD/src/meson.build
@@ -214,8 +214,9 @@ if get_option('enable-autodiff')
  su2_cfd_lib_ad = static_library('SU2core_AD',
                               su2_cfd_src,
                               install : false,
-		               dependencies : [su2_deps, codi_dep, commonAD_dep],
-                               cpp_args: [default_warning_flags, su2_cpp_args, codi_rev_args])
+                               dependencies : [su2_deps, codi_dep, commonAD_dep],
+                               cpp_args: [default_warning_flags, su2_cpp_args, codi_rev_args],
+                               override_options: ['cpp_std=c++17'])
  su2_cfd_dep_ad = declare_dependency(link_with: su2_cfd_lib_ad,
                                   include_directories: su2_cfd_include)
  su2_cfd_ad = executable('SU2_CFD_AD',
@@ -223,6 +224,7 @@ if get_option('enable-autodiff')
                          install : true,
                          dependencies : [su2_cfd_dep_ad, su2_deps, codi_dep, commonAD_dep],
                          cpp_args: ['-fPIC'] + [default_warning_flags, su2_cpp_args, codi_rev_args] + profiling_args,
+                          override_options: ['cpp_std=c++17'],
                          link_args: profiling_args)
endif

• Adding and if before the project: Not allowed
• Using a ternarry in the project: Command line arguments are not available yet.
• Changing these default project options afterwards is not possible.
• Leaving the cpp option and adding compiler flags afterwards: This would probably work but does not allow the user anymore to overwrite it via the command line.

Maybe I missed something, but changing the version globally has currently the least headaches.

Is there some documentation that needs to be changed?

PR Checklist

Put an X by all that apply. You can fill this out after submitting the PR. If you have any questions, don't hesitate to ask! We want to help. These are a guide for you to know what the reviewers will be looking for in your contribution.

• [ X] I am submitting my contribution to the develop branch.
• [ X] My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
• [ X] My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
• [ X] I used the pre-commit hook to prevent dirty commits and used pre-commit run --all to format old commits.
• [ X] I have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

[MaxSagebaum]

Thanks.