Common Install process for linux/UNIX.

1: compile/install libosip first.

  $> tar -xvzf libosip2-x.x.x.tar.gz
  $> CFLAGS="-I/usr/local/include/" ../configure
  $> make
  $> make install      (as root...)

2: compile/install eXosip

  $> tar -xvzf libeXosip2-x.x.x.tar.gz
  $> CFLAGS="-I/usr/local/include/" ../configure
  $> make
  $> make install      (as root...)