g++ command -lgc-lib error, how can I install the libgc?

I compiled a C# file to llvm IR file by il2bc(https://github.com/FrankLIKE/il2bc)

But when I compile a Helloworld C# file to obj follow that tutorial,and want to compile it to a executable file by g++ command:

g++ -o helloworld.exe helloworld.obj CoreLib.obj -lstdc++ -lgc-lib -march=i686 -L .

but g++ return a error:

c:/mingw/bin/../lib/gcc/mingw32/6.3.0/../../../../mingw32/bin/ld.exe: cannot find -lgc-lib
collect2.exe: error: ld returned 1 exit status

and I try to remove the command -lgc-lib and compile return me a lots of GC(garbage-collection) error. I think the gc-lib must be a C++ GC lib, but I cannot find it in gcc lib path.

I want to know what wrong with it and how to install the lib to run that command.

my OS is Windows10 .using MinGW g++ to compile.