Build fails if INL=1

$ cmake -DCMAKE_INSTALL_PREFIX:PATH=/tmp/netrek/ -DINL:BOOLEAN=True ..
<snip>
Linking C executable basep
cd /Users/tanner/projects/netrek/netrek-server/Vanilla/build/robots && /opt/local/bin/cmake -E cmake_link_script CMakeFiles/basep.dir/link.txt --verbose=1
/usr/bin/gcc -g -flat-namespace;-Wl,-search_paths_first -headerpad_max_install_names -fPIC CMakeFiles/basep.dir/basep.o CMakeFiles/basep.dir/commands_basep.o CMakeFiles/basep.dir/roboshar.o -o basep ../ntserv/libnetrek.a /usr/lib/libm.dylib
Undefined symbols:
  "_do_uncaptain", referenced from:
      _commands in commands_basep.o
  "_do_captain", referenced from:
      _commands in commands_basep.o
  "_do_resetgalaxy", referenced from:
      _commands in commands_basep.o
  "_do_switchside", referenced from:
      _commands in commands_basep.o
      _commands in commands_basep.o
  "_do_confine", referenced from:
      _commands in commands_basep.o
  "_do_pickside", referenced from:
      _commands in commands_basep.o
      _commands in commands_basep.o
      _commands in commands_basep.o
      _commands in commands_basep.o
      _commands in commands_basep.o
  "_do_tname", referenced from:
      _commands in commands_basep.o
  "_do_free", referenced from:
      _commands in commands_basep.o
  "_do_gametime", referenced from:
      _commands in commands_basep.o
  "_do_timeout", referenced from:
      _commands in commands_basep.o
  "_do_start", referenced from:
      _commands in commands_basep.o
  "_do_pause", referenced from:
      _commands in commands_basep.o
      _commands in commands_basep.o
      _commands in commands_basep.o
ld: symbol(s) not found
collect2: ld returned 1 exit status