Please help me debug my C++ code

[davin....@gmail.com]

Here is the location of my files:

http://davinpearson.com/binaries/map-20180403-100601.tar.gz

When I try to link map/map.cc it gives me the following
error message:

-*- mode: compilation; default-directory: "~/lisp++-projects/" -*-
Compilation started at Tue Apr 3 09:54:15

cd ~/lisp++-projects && make 2018/map/map.run
* Compiling 2018/map/map.cc DEBUG
g++ -g -O0 -std=c++11 -W -Wall -Wpointer-arith -Wformat -ffast-math -fno-permissive -Wno-format-contains-nul -c 2018/map/map.cc -o 2018/map/map.o
** Linking 2018/map/map.exe DEBUG
g++ -lgcc -lstdc++ 2018/map/map.o 2006/libd/libd.o -o 2018/map/map.exe
2018/map/map.o: In function `main':
/home/www/lisp++-projects/2018/map/map.cc:67: undefined reference to `operator<<(dmp::Writer&, std::map<dmp::string, int, std::less<dmp::string>, std::allocator<std::pair<dmp::string const, int> > > const&)'
/home/www/lisp++-projects/2018/map/map.cc:72: undefined reference to `operator<<(dmp::Writer&, std::map<dmp::string, int, std::less<dmp::string>, std::allocator<std::pair<dmp::string const, int> > > const&)'
collect2: error: ld returned 1 exit status
Makefile.mk:86: recipe for target '2018/map/map.exe' failed
make: *** [2018/map/map.exe] Error 1

Compilation exited abnormally with code 2 at Tue Apr 3 09:54:18
Compilation started at: 20180403-095415
compilation-start-time=(23234 42631 170126 679000)
compilation-stop-time=(23234 42634 38836 734000)
Compilation took 3 seconds

Any help with how to get around this compiler error would
be gratefully appreciated.