There is a GPL version labelled as “A C refactoring tool for emacs” at http://sourceforge.net/projects/c-xref/files/ All other references to the original Xrefactory seems to be gone…
Here's a write up of recent experience with it.
[old] Xrefactory is a tool for C and C++ providing code completion, source browsing and refactoring.
The older releases of Xrefactory that work with Emacs are “no-cost” (gratis) – with the restriction that you are not allowed to resell the software. Redistributions free of charge are allowed. Attempts to encourage the owners to release the code under a free license have not had any results. The C++ version has remained fully proprietary.
It seems very impressive, but does it deliver what it claims?
I used Xrefactory in my previous job, on a fairly large Java code base referencing many libraries. It worked pretty well, especially the “semantic” tab completion and code navigation. The C/Java version is now apparently free (used to be $29), but I don’t know if it is still being updated (the downloadable version does not support newer JDKs). --Damien Diederen
These products (xrefactory c/java, xrefactory c++) seems to be abandoned. The c++ version does not work very well with recent c++ code (like one found in new versions of boost).