Bugzilla bug #25981: sysconf(_SC_NPROC_ONLN) on SINIX-Z 5.42 and

SINIX-N 5.43 fails with EINVAL.  Don't know why.  So backed it out.

nsprpub/pr/src/misc/prsystem.c

@@ -180,7 +180,7 @@ PR_IMPLEMENT(PRInt32) PR_GetNumberOfProcessors( void )
         numCpus = -1; /* set to -1 for return value on error */
         PR_SetError( PR_UNKNOWN_ERROR, _MD_ERRNO());
     }
-#elif defined(IRIX) || defined(RELIANTUNIX)
+#elif defined(IRIX)
     numCpus = sysconf( _SC_NPROC_ONLN );
 #elif defined(XP_UNIX)
     numCpus = sysconf( _SC_NPROCESSORS_ONLN );