Follow GNU CLI conventions for options: e.g. accept `-T=4` and `-T4` not just `-T 4`

[corneliusroemer]

I've noticed that the CLI interface doesn't allow common patterns used by most CLI tools, concretely: "don't require args to be passed after whitespace, also accept after = and when being a short arg allow them directly (-T4 is same as -T 4)

Right now I get this:

$ ./cmaple -T4
Invalid "-T4" option.
$ ./cmaple -T=4
Invalid "-T=4" option.

This is a great guide for making nice CLIs: https://clig.dev/#arguments-and-flags

Some concrete libraries you could use:

• https://github.com/p-ranav/argparse
• https://github.com/jarro2783/cxxopts
• https://github.com/CLIUtils/CLI11
• https://www.boost.org/doc/libs/1_81_0/doc/html/program_options.html