meaning of ld error message "duplicate version tag" - matlab

Question

I'm compiling some C++ functionality into Matlab by using Mex compilation to produce a .mexa64 binary.
Honestly I don't know much about the guts of the symbols created in the .mexa64 binary and how it allows Matlab to call C++, but I'm starting with a simple question related to the error I eventually get when the command mex calls ld.
The ld error is:
/usr/bin/ld.real: duplicate version tag `MEX'
The question is, what does this ld error "duplicate version tag" mean? Other appreciated perspectives are: what does it mean in relation to the Matlab compilation I'm trying to do specifically; and where can I find comprehensive ld error message documentation?
This latter point, the comprehensive ld documentation, I've found particularly hard to find. The manual page for ld didn't seem to be helpful for this.
requested to post the mex config file:
<config Name="g++" ShortName="g++" Manufacturer="GNU" Version="" Language="C++" Priority="A" Location="$GCC_DIR">
<Details CompilerExecutable="$CXX" CompilerDefines="$DEFINES" CompilerFlags="$CXXFLAGS" OptimizationFlags="$CXXOPTIMFLAGS" DebugFlags="$CXXDEBUGFLAGS" IncludeFlags="$INCLUDE" LinkerLibraries="$LINKLIBS" LinkerOptimizationFlags="$LDOPTIMFLAGS" LinkerDebugFlags="$LDDEBUGFLAGS" CompilerDefineFormatter="-D%s" LinkerLibrarySwitchFormatter="-l%s" LinkerPathFormatter="-L%s"/>
<vars CMDLINE1="$CXX -c $DEFINES $INCLUDE $CXXFLAGS $OPTIM $SRC -o $OBJ" CMDLINE2="$LDXX $LDFLAGS $LDTYPE $LINKOPTIM $LINKEXPORT $OBJS $CXXLIBS $LINKLIBS -o $EXE" CMDLINE3="rm -f $OBJ" CXX="$GCC" DEFINES="-D_GNU_SOURCE $MATLABMEX" MATLABMEX="-DMATLAB_MEX_FILE " CXXFLAGS="-ansi -fexceptions -fPIC -fno-omit-frame-pointer -pthread -std=c++11" INCLUDE="-I"$MATLABROOT/extern/include" -I"$MATLABROOT/simulink/include"" CXXOPTIMFLAGS="-O -DNDEBUG" CXXDEBUGFLAGS="-g" LDXX="$CXX" LDFLAGS="-pthread -Wl,--no-undefined " LDTYPE="-shared" LINKEXPORT="-Wl,--version-script,"$MATLABROOT/extern/lib/$ARCH/mexFunction.map"" LINKLIBS="-Wl,-rpath-link,$MATLABROOT/bin/$ARCH -L"$MATLABROOT/bin/$ARCH" -lmx -lmex -lmat -lm -lstdc++" LDOPTIMFLAGS="-O" LDDEBUGFLAGS="-g" OBJEXT=".o" LDEXT=".mexa64"> </vars>
<client>
<engine LINKLIBS="$LINKLIBS -leng" LINKEXPORT="" LDEXT="" LDTYPE=""/>
<mbuild DEFINES="-D_GNU_SOURCE $MATLABMEX -DUNIX -DX11 -DGLNXA64 -DGCC" CXXFLAGS="-ansi -pthread -std=c++11" INCLUDE="$INCLUDE -I"$MATLABROOT/extern/include/cpp"" LDFLAGS="-pthread -Wl,-rpath-link,$MATLABROOT/bin/$ARCH" LINKEXPORT="" LINKLIBS="-L"$MATLABROOT/runtime/$ARCH" -lm -lmwmclmcrrt" LDEXT="" MATLABMEX="" LDTYPE=""/>
</client>
<locationFinder>
<GCC>
<cmdReturns name="which g++"/>
</GCC>
<CPPLIB_DIR>
<cmdReturns name="g++ -print-file-name=libstdc++.so" diagnostic="GCC appears to be installed, but supporting C++ libraries were not found. You must first install the gcc-c++ packge, or similiar, to complete this action."/>
</CPPLIB_DIR>
</locationFinder>
</config>