go build filename
用于编译，
在编译之前需要把当前工程目录(src目录的父目录) export到GOPATH
go在编译文件filename的时候会自动寻找依赖，比如寻找GOPATH目录下的src下的cg目录和ipc目录
build的-x选项用于输出详细编译信息

song@ubuntu:~/gobook-src/chapter4/cgss/src$ ls -l
total 12
drwxrwxr-x 2 song song 4096 Jun 25 00:26 cg
-rwxrwxr-x 1 song song 2906 Jun 25 00:26 cgss.go
drwxrwxr-x 2 song song 4096 Jun 25 00:26 ipc

song@ubuntu:~/gobook-src/chapter4/cgss/src$ go build -x cgss.go
WORK=/tmp/go-build423507130
mkdir -p $WORK/command-line-arguments/_obj/
mkdir -p $WORK/command-line-arguments/_obj/exe/
cd /home/song/gobook-src/chapter4/cgss/src
/usr/local/go/pkg/tool/linux_amd64/compile -o $WORK/command-line-arguments.a -trimpath $WORK -p main -complete -buildid 7d8322f4be13db970a7735a1c1c5429a89836db0 -D _/home/song/gobook-src/chapter4/cgss/src -I $WORK -I /home/song/gobook-src/chapter4/cgss/pkg/linux_amd64 -pack ./cgss.go
cd .
/usr/local/go/pkg/tool/linux_amd64/link -o $WORK/command-line-arguments/_obj/exe/a.out -L $WORK -L /home/song/gobook-src/chapter4/cgss/pkg/linux_amd64 -extld=gcc -buildmode=exe -buildid=7d8322f4be13db970a7735a1c1c5429a89836db0 $WORK/command-line-arguments.a
mv $WORK/command-line-arguments/_obj/exe/a.out cgss