The RTC code is done, and will be included with next release of the "Netcruzer Download". Will also contain an RTC demo project. You can try the following. I hope I have included all steps required for adding to an old project. Please let me know if it compiles.
1) Replace your "../src/netcruzer/lib" files with files contained in the attached lib_20140428-1010.zip (make backup of existing file first!). I don't think you should have made any changes to these files.
2) Add new RTC files "nz_rtc.c" and "nz_rtc.h" to your MPLAB X project.
3) Add following line to the file you want to use the new RTC functions in:
#include "nz_rtc.h"
4) Add following lines to your projdefs.h file:
// *********************************************************************
// ------------ RTC Configuration (from nz_rtc.h) -------------
// *********************************************************************
#define NZ_RTC_ENABLED (1) //Enable RTC
#define NZ_RTC_UNLOCK (1) //Unlock RTC during initialization
5) You should now be able to use the new RTC code. See included demo project for examples how to use it.
6) FOR EXAMPLE (taken from demo project), to set time:
RTC_TIME tm;
tm.hour = 11;
tm.min = 40;
tm.sec = 50;
rtcSetTime(&tm);
7) FOR EXAMPLE (taken from demo project), to get time:
RTC_TIME tm;
rtcGetTime(&tm, 0); //Get time in standard binary format
printf("\nTime: %02d:%02d:%02d", tm.hour, tm.min, tm.sec);

FOR EXAMPLE (taken from demo project), to get time and date:
RTC_TIME_AND_DATE td;
rtcGetTimeAndDate(&td, 0); //Get time and date in standard binary format
printf("\nTime: %02d:%02d:%02d, Date: %02d-%02d-%d", td.hour, td.min, td.sec, td.day, td.month, td.year+2000);