Adding support for MacOS

[fr0zn]

Correctly checking for all dependencies required on MacOS. Recommending the user to force the linkage of e2fsprogs, which will be linked under /usr/local/sbin. (Maybe an export PATH="/usr/local/sbin:$PATH is needed for some users)

[nongiach]

Oups, my bad I didn't merge #17

now we have two pull request doing the same thing :/
I will test if your pull request works on debian and I will merge it because it looks more complete than the other one. Can you confirm that you tested with several options several times?
Thx and great work you both.

For the distribution function It would be nice to not rename Darwin to macos, I don't see the point of doing it, is there a reason?
Can you take a look at this: 9e534ee

Thx.

[fr0zn]

Ok, I decided not to rename darwin. I couldn't find a way to make -serial stdio -monitor /dev/null work on macOS. Getting -monitor /dev/null: 'serial' is not a valid char driver name. That's why I decided to erase that option in darwin in the first place.

On the last commit I found a way to solve that issue, setting -monitor to null (without dev). That change needs to be checked against other linux distributions.

Also:
From the man page: -serial and -monitor is set to stdio by default in non graphical mode.

[nongiach]

nice, I'm gonna check this out

[nongiach]

Merged!
The opensource community thanks you for your service.
Do you have some feedback about some things that we can improve to ease pull requests?
For example, I know that we should have an automated unit test ^^
Thx