If a run the method 'drush status' in the terminal I see that the values for 'Drush configuration' and 'Php configuration' are missing.
It give me not problem at all. But is this correct?
Look the capture:
I use the free version of MAMP.

One of my colleagues has MAMP installed and that's what his Drush status looks like too.
I'm using the build of Apache built in to OSX and the only difference I see is that the PHP configuration is filled in:

Like you, neither my colleague or I suffer any problems with these settings missing so I wouldn't worry too much about it.