In versions from 5.6 onwards on OSX Lion there are problems when generating an emacs TAGS file, even if you simply pass -x to show the table.
The output always contains (possibly in addition to other errors), the line:
(where 22 might be a different number depending on the file)
I tested this with the simplest possible files. When called with a list of files (-L) or recursively on a directory, only the first file seems to generate this invalid tag (but other invalid entries exist, such as "^^,120" and "/var/folders/m7/6b_4vfzx06b9mg52lc9d31r0001jmd/T//tags.l1LmvG,2960".
I have tried configuring using --disable-external-sort.
I am unable to configure versions before /tags/CTags-5_6 because of errors during configure (cannot find ./install.sh, unable to guess build system).