The available unmerged changes as of 16012024

[andriish]

Dear @gavinsalam,
here are the remaining unmerged changes as of today.
The changes include:

• Attempts to modernize the code and make in compatible with more compilers
  • replace $ sign
  • replace the non-standard functions of Fortran77 such as system with the standard equivalent from Fortran200x
• Extensions of CI with more compilers
• Workaround for the compilers that treat the ubound/lbound incorrectly

In addition, what one could do with the hoppet code is

• drop the scripts such as test.sh, tarit.sh -- the functionality of those scripts is implemented in cmake and github/gitlab.
• drop the make/mkmk-based build system - benchmarking/mkmk, mkmk, scripts/ etc. It is superseded by the cmake.
• avoid using the links in the source tree

Best regards,

Andrii