Golang go-sql-driver / mysql.a

I'm using "github.com/go-sql-driver/mysql" library on CentOS6.6 server.
And import the library:

import (
    _ "github.com/go-sql-driver/mysql"
)

Building

go build index.go

However, an error occurred.

import /usr/local/go/pkg/linux_amd64/github.com/go-sql-driver/mysql.a: object is [darwin amd64 go1.4.2 X:precisestack] expected [linux amd64 go1.4 X:precisestack]

I don't know what this error says.

Please tell me how to solve this problem.

As said here, with this kind of error, deleting the pkg folder often helps