Execution go build -buildmode = c-shared -o exportgo.dll exportgo.go message similar to the following error
/usr/lib/gcc/x86_64-pc-msys/9.1.0/../../../../x86_64-pc-msys/bin/ld: Can not find -lmingwex
/ usr / lib / gcc /x86_64-pc-msys/9.1.0/../../../../x86_64-pc-msys/bin/ld: Can not find -lmingw32
Installation tdm gcc mingw solve the problem.