gdbstub support

[hamid-rostami]

This PR is to add debug capability to emulated risc-v applications.
gdbstub implementation uses GDB remote serial protocol and act as a server. GDB as a client can connect to it and start debugging the app.
Support for uvm32 is added to the following gsbstub implementation which I'm going to open a PR for it as well:
https://github.com/mborgerson/gdbstub

For simplicity, I just included gdbstub.h file in my example.

[ringtailsoftware]

Thank you for this, looks great. I will take a look in the next few days and hopefully merge.

[hamid-rostami]

Thank you for this, looks great. I will take a look in the next few days and hopefully merge.

Thanks @ringtailsoftware, let me know how you're getting on.
I might also have broken some unit tests, I'll have a look today.

[ringtailsoftware]

Thanks. I've modified this a little to make ebreak trapping optional, so it doesn't break the existing tests.
a72737b

[hamid-rostami]

Thanks @ringtailsoftware for accepting this PR.
I just forgot to update the project readme to mention this feature. I can open a new PR for that, or else I'd appreciate it if you could update it.

[ringtailsoftware]

0e808a9

[hamid-rostami]

0e808a9

That's great, just the link is broken because of an extra space character between () and []