Error Compile in Arduino Sketch

Dear DLMS Experts,

I try to compile DLMS source code with Arduino Mega 2560. I already copy the src and include folder from development folder into the Arduino_IDE server folder. I click the compile button then Arduino IDE displays an error. Please see my attachments.
Is there any file to edit ? Hope my attachment could help you to find the problem. Thank you.

The error :
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C:\Users\RNDSMI\AppData\Local\Temp\arduino_build_405699\sketch\include/variant.h:98:9: note: type 'union <anon>' itself violates the C++ One Definition Rule
{
^
C:\Users\RNDSMI\AppData\Local\Temp\arduino_build_405699\sketch\include/variant.h:139:7: note: type 'struct dlmsVARIANT' should match type 'struct dlmsVARIANT'
} dlmsVARIANT;
^
C:\Users\RNDSMI\AppData\Local\Temp\arduino_build_405699\sketch\include/gxvalueeventargs.h:127:7: note: type 'struct gxValueEventCollection' itself violates the C++ One Definition Rule
} gxValueEventCollection;
^
C:\Users\RNDSMI\AppData\Local\Temp\arduino_build_405699\sketch\include/variant.h:139:7: note: type 'struct dlmsVARIANT' should match type 'struct dlmsVARIANT'
} dlmsVARIANT;
^
C:\Users\RNDSMI\AppData\Local\Temp\arduino_build_405699\sketch\include/dlmssettings.h:183:7: note: type 'struct dlmsSettings' itself violates the C++ One Definition Rule
} dlmsSettings;
^
C:\Users\RNDSMI\AppData\Local\Temp\arduino_build_405699\sketch\include/dlmssettings.h:240:7: note: type 'struct dlmsServerSettings' itself violates the C++ One Definition Rule
} dlmsServerSettings;
^
C:\Users\RNDSMI\AppData\Local\Temp\arduino_build_405699\sketch\include/gxarray.h:58:7: note: type 'struct gxArray' itself violates the C++ One Definition Rule
} gxArray;
^
C:\Users\RNDSMI\AppData\Local\Temp\ccLCni3n.ltrans2.ltrans.o: In function `sendPush(dlmsSettings*, gxPushSetup*) [clone .part.39] [clone .constprop.103]':

D:\SMI\Modem\GuruxDLMS.c-master\Arduino_IDE\server/server.ino:1559: undefined reference to `mes_attach'

collect2.exe: error: ld returned 1 exit status

Using library EEPROM at version 2.0 in folder: C:\Program Files (x86)\Arduino\hardware\arduino\avr\libraries\EEPROM

exit status 1

Error compiling for board Arduino Mega or Mega 2560.
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Regards,
Mahendra