This is makeindex, version 2.15 [TeX Live 2015] (kpathsea + Thai support).
Scanning input file gthmanual-tmp.idx....done (251 entries accepted, 0 rejected).
Sorting entries.....done (2208 comparisons).
Generating output file gthmanual-tmp.ind....done (239 lines written, 0 warnings).
Output written in gthmanual-tmp.ind.
Transcript written in gthmanual-tmp.ilg.
