This is the source repository of the CRAN package patchSynctex. People wishing to access Jan Gleixner's patchKnitrSynctex may do so on its own Github page https://github.com/jan-glx/patchKnitrSynctex. An archival copy of its state when I forked this program is available at https://github.com/EmmanuelCharpentier/patchKnitrSynctex, but is, intentionally, not maintained.
I choose to ignore the standalone C++ program, which is difficult to maintain cross-platform, and concentrated on the R version.
Install the package in your R installation and peruse the help pages of the package.
Have fun !