To apply this patch to a fresh nauty22 source:

First download and extract the nauty 2.2 source by Brendan McKay at
http://cs.anu.edu.au/~bdm/nauty/

Then copy the files dynstr.c dynstr.h mynauty.c mynauty.h to the nauty22
directory.

Then go one directory higher (the directory that has nauty22 as a
subdirectory) and type:
patch < $PATH/nauty22-diff