[R-SIG-Mac] Problems with lzma headers file compiling R 3.3.1 under mac os x 10.7.5

[Vittorio De Martino]

I'm trying for the first time to compile R 3.3.1 on my old macbook with 10.7.5.
Among other things I have already successfully installed the xz port (which includes lzma) from the macports collection (xz-devel is now included in xz).
When as root user I launch  './configure'  the configure process stops with the following error:

$ ./configure
...........
...........
checking if bzip2 version >= 1.0.6... yes
checking whether bzip2 support suffices... no
checking for lzma_version_number in -llzma... no
configure: error: "liblzma library and headers are required"

I'm getting stuck here. Please help
Ciao
Vittorio