tramp 2.1.3 install problem - bug or mis-configured?

[Paul Lew]

When I specify the install dir with:

    make install prefix=$tools/kit/tramp-2.1.4/auto/insbu-cnstools

It executed with:
    ...
    mkdir -p /auto/insbu-cnstools/share/emacs/site-lisp
    install -m644 trampver.el tramp.el tramp-cache.el tramp-smb.el
                  tramp-util.el tramp-uu.el tramp-vc.el tramp-ftp.el
                  trampver.elc tramp.elc tramp-cache.elc tramp-smb.elc
                  tramp-util.elc tramp-uu.elc tramp-vc.elc
                  tramp-ftp.elc
                  /auto/insbu-cnstools/share/emacs/site-lisp

instead of the prefix specified on the make install command line.

This was the prefix given in the configure step:

    ./configure --with-cotrib
                --prefix=/auto/insbu-cnstools/share/emacs/site-lisp

Is this a bug?  The previous 2.1.3 has no such problem.

Thanks in advance.