Impossible to specify NFO file version (header comment is ignored)
A NFO version 32 source file has to start with the proper grfcodec comment at the start of the file as otherwise NFOrenum will interpret it as some other version. Supplying said header in the main NFO file is currently not possible with the default Makefile settings as these cause the preprocessor to emit linemarkers which will be printed before the first line of the input file (and have the interesting side effect of making NFOrenum assume a NFO version 7).
It is fixable by adding the option -P to CC_FLAGS (which suppresses the linemarkers. nmlc OTOH might need the linemarkers, and CC_FLAGS is not format-specific). Existing code without a NFO header comment will completly break though. The example file's .nfo starts with a // comment (from headers.pnfo) that is not the standard format comment, which causes NFOrenum to assume a NFO version 4. Deleting this comment makes NFOrenum fail completely. Ergo, if -P is given, the NFO header comment has to be in the NFOrenum input as well.