make: fix GCC warnings

*** 109,119 ****
                          return 0; /* success */
                  }
                  UNBLOCK_INTERUPTS;
  
                  if (errno != EEXIST) {
!                         file_lock_error(msg, name, NOCATGETS("symlink(%s, %s)"),
                              (int) name, (int) lockname);
                          fprintf(stderr, "%s", msg);
                          return errno;
                  }
  
--- 109,119 ----
                          return 0; /* success */
                  }
                  UNBLOCK_INTERUPTS;
  
                  if (errno != EEXIST) {
!                         file_lock_error(msg, name, (char *)NOCATGETS("symlink(%s, %s)"),
                              (int) name, (int) lockname);
                          fprintf(stderr, "%s", msg);
                          return errno;
                  }