Download go.o and run
gcc -i a.out.exe go.o
go.o is one of the object files produced by go build of main.go and included in the original linking command that failed
gcc -m64 -mconsole -Wl,--tsaware -Wl,--nxcompat -Wl,--major-os-version=6 -Wl,--minor-os-version=1 -Wl,--major-subsystem-version=6 -Wl,--minor-subsystem-version=1 -Wl,--dynamicbase -Wl,--high-entropy-va -o C:\msys64\tmp\go-build323995550\b001\exe\a.out.exe -Wl,--no-insert-timestamp C:\msys64\tmp\go-link-201239192\go.o C:\msys64\tmp\go-link-201239192\000000.o C:\msys64\tmp\go-link-201239192\000001.o C:\msys64\tmp\go-link-201239192\000002.o C:\msys64\tmp\go-link-201239192\000003.o C:\msys64\tmp\go-link-201239192\000004.o C:\msys64\tmp\go-link-201239192\000005.o C:\msys64\tmp\go-link-201239192\000006.o C:\msys64\tmp\go-link-201239192\000007.o C:\msys64\tmp\go-link-201239192\000008.o C:\msys64\tmp\go-link-201239192\000009.o -O2 -g -lcfgmgr32 -O2 -g -Wl,-T,C:\msys64\tmp\go-link-201239192\fix_debug_gdb_scripts.ld -Wl,--start-group -lmingwex -lmingw32 -Wl,--end-group -lkernel32