After upgrading Lion to Mountain Lion, the MacPorts system seems broken.
Refering to the MacPorts's migration page, the best solution seems to unistall all and reinstall all the ports.
Is there a simpler/less drastic solution?
Here is how I fix it (after Mountain Lion update):
sudo xcodebuild -license.
sudo port install [something]or others, you'll have the following return: Error: org.macports.build for port libunwind-headers returned: command execution failed
sudo port selfupdate
sudo port upgrade outdated
After that, everything works except MongoDB, After some research, I found this article (How to upgrade MacPorts to OS X 10.8 Mountain Lion) by Phil Freo.
Thanks to this article, which reassured me in my approach, I also found the solution to my last issue:
Everything finished and worked properly except MongoDB. Currently there is an incompatibility between boost 1.50 and MongoDB which can be resolved with these two commands, assuming boost 1.49 was previously installed on your machine:
sudo port activate boost @1.49.0_0
sudo port -n install mongodb