fix err: zlib.h: No such file or directory, Just used by bitmap.

SET CGO_ENABLED=1
SET GOARCH=386
go build main.go

sudo apt install gcc-multilib
sudo apt install gcc-mingw-w64
# fix err: zlib.h: No such file or directory, Just used by bitmap.
sudo apt install libz-mingw-w64-dev

GOOS=windows GOARCH=amd64 CGO_ENABLED=1 CC=x86_64-w64-mingw32-gcc CXX=x86_64-w64-mingw32-g++ go build -x ./

// CC=mingw-w64\x86_64-7.2.0-win32-seh-rt_v5-rev1\mingw64\bin\gcc.exe
// CXX=mingw-w64\x86_64-7.2.0-win32-seh-rt_v5-rev1\mingw64\bin\g++.exe