libtiff comes without LZW compression support. The Unisys patent on LZW has now expired everywhere. It can be added back in. I can provide a spec file that builds libtiff with LZW compression (using the libtiff-lzw-compression-kit-1.5.tar.gz package) if necessary.
The libtiff website contains the following comment on lzw compression: It appears that Unisys is actively pursuing copyright control on the LZW compression algorithm. In particular, users of the LZW compression within the TIFF framework. For this reason the TIFF 6.0 spec states that LZW compression is not recommended. It is unclear at this time what compression algorithm will be used in place of it. I have no idea what this means to you or to this library. I make no warranty or guarantees with regard to the LZW support in this library.
You looked at an outdated version of the webpage. The mirrored page at http://www.libtiff.org/misc.html is dated 2003/12/23 10:28:17, the authorative page at http://www.remotesensing.org/libtiff/misc.html is dated 2004/08/11 05:11:25 and no longer carries this notice. Please reconsider.
Sven, if we would upgrade libtiff to 3.7.1, lzw support is a) delivered directly with libtiff and b) could be also enabled; see bug #143560.