I use the go Tool: go get github.com/go-sql-driver/mysql
and get the response
cd .; git clone https://github.com/go-sql-driver/mysql /Users/arnold/Documents/CSUF/CSci130/goworkspace/src/github.com/go-sql-driver/mysql
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun
package github.com/go-sql-driver/mysql: exit status 1
What does it mean?