Perform the following steps

1. Get latest IMP version.

2. Get latest development version
To get the latest development version of MultiFit, it is necessary to check it out from our MultiFit repository using an Subversion client:
svn co https://svn.salilab.org/multifit/ multifit
This will create a directory called multifit containing all the source at the SVN.

3. Update scons environment in $MULTIFIT update SConstruct file:
update imp to its correct path

4. Build:
in $MULTIFIT run: scons -j2