The patch has been submitted for upstream inclusion, but the TinTin++ maintainer was not interested in including this feature, so it is being maintained out-of-tree.
To apply it, run patch -p4 < file.patch from the base directory of the TinTin++ source tarball, then you might want to make clean before rebuilding.
In the 0.2 revision you simply supply an integer to #config wordwrap to enable wrapping at the N'th column.
Download:
Patch revision 0.2 for TinTin++ 1.98.0 (applies cleanly to 1.99.6) (MD5: 7150b79ee485b6cf641861c9b95996a7)
Older patches
Patch revision 0.1.1 for TinTin++ 1.98.0 (MD5: 888561578c746d7951ecc83ac68346da)
Patch revision 0.1 for TinTin++ 1.97.9 (applies cleanly to 0.98.0) (MD5: 8f200232fd256c543fc964a167a2c221)