Deactivating the includes for libsndfile solved my issue with sound on linux.

In trunk/dev/var/scons/thirdparty/libsndfile.py at line 23:

replace:

    params['includePath'].append('libsndfile/include')

by:

    if sys.platform!='linux2' and sys.platform!='linux3':
        params['includePath'].append('libsndfile/include')

NB: indentation is made with some blankspaces, not tabs.

File libsndfile.so must be renamed libsndfile.so.1

If a linux user who has no problem with sound could try to build with this modification would let us know if this is a generic fix or a custom fix.
Linux users who have no sound are encouraged to try this fix and report feedback.