newer versions of perl may not have 'switch' -- relevant for config

[bsu-wrudisill]

EDITED 9/23 for clarity It appears that not all versions of perl have the 'switch' module installed as a default, and I found it somewhat difficult to install the switch module on my system. 'Switch' is used in the .config script, located here:

https://github.com/NCAR/hrldas/blob/e6853efc84d884836122e42e02a9ea2e748ec75b/hrldas/configure#L26

Based on my reading it sounds like the 'given/when' syntax is preferred with new versions of perl. With the aid of a ChatGPT, I was able to replace the switch statements with given/when which appears to work:

---

#!/usr/bin/perl
use feature 'switch';

if ($#ARGV == 0) {
    $response = shift(@ARGV);
    print("Configure HRLDAS: $response \n");
} else {
    print "Please select from the following supported architectures: \n\n";

    print "   1. Linux PGI compiler serial \n";
    print "   2. Linux PGI compiler MPI \n";
    print "   3. Linux intel compiler serial \n";
    print "   4. Linux intel compiler MPI \n";
    print "   5. Linux intel compiler MPI (NCAR/Derecho) \n";
    print "   6. Linux gfortran/gcc compiler serial \n";
    print "   7. Linux gfortran/gcc compiler MPI \n";
    print "   8. Linux gfortran/gcc compiler MPI (NCAR/Derecho) \n";
    print "   9. Linux gfortran/gcc compiler MPI (Docker container) \n";
    print "   0. exit only \n";

    printf "\nEnter selection [%d-%d] : ", 0, 9;

    $response = <STDIN>;
    chomp($response);
}

given ($response) {
    when (1) {
        # serial PGI
        system "cp arch/user_build_options.pgi.serial user_build_options";
    }
    when (2) {
        # MPI PGI
        system "cp arch/user_build_options.pgi.mpi user_build_options";
    }
    when (3) {
        # serial intel
        system "cp arch/user_build_options.ifort.serial user_build_options";
    }
    when (4) {
        # MPI intel
        system "cp arch/user_build_options.ifort.mpi user_build_options";
    }
    when (5) {
        # MPI intel (NCAR/Derecho)
        system "cp arch/user_build_options.ifort.mpi.derecho user_build_options";
    }
    when (6) {
        # serial GFORTRAN
        system "cp arch/user_build_options.gfortran.serial user_build_options";
    }
    when (7) {
        # MPI GFORTRAN
        system "cp arch/user_build_options.gfortran.mpi user_build_options";
    }
    when (8) {
        # MPI GFORTRAN (NCAR/Derecho)
        system "cp arch/user_build_options.gfortran.mpi.derecho user_build_options";
    }
    when (9) {
        # MPI GFORTRAN for Docker container
        system "cp arch/user_build_options.gfortran.mpi.container user_build_options";
    }
    default {
        print "no selection $response\n";
        last;
    }
}

print "The user_build_options file used for compiling source code has been successfully generated. \n";
print "Please check and change the software package path in the generated user_build_options file before compiling! \n";