To install the Mozart Standard Library, you should have Mozart already
installed on your system. Let us assume that Mozart is installed in
$PREFIX. 

Now, to build the Standard Library, it is a good idea to do it in a
different directory from the sources. Let us consider $STDLIB for the
sources and $BUILD_STDLIB for building. You should do the following:

cd $BUILD_STDLIB
$STDLIB/configure --prefix=$PREFIX
make
make install