OK, Gale, so there is an almost cubic relation between repairlen and processing time, due to the use of matrices.
However there is no need to restrict the repairlen to a value being a power of 2: e.g. 200 would do also!
Assuming that your computer is set up to build Audacity, why don’t you try it both ways?
If your computer is not yet set up to build Audacity, do that first and ensure that you are able to build (and run) the official, unmodified source code.
(From a quick look at the code, it seems to me that the first line that you identified enforces the 128 sample limit, and the second line that you identified relates to the space around the selection that is used to calculate the interpolated repair. I may be wrong - I only took a quick look.)
You only need to change line 97, though you may want to update the comments at lines 112, 126 and 129.
“spacing” ensures that there is some data on which to base the reconstruction of the waveform.