Fixes for multiplatform dev and testing from forks (#7734)

Add support for correct dependency URLs on all platforms

only build mountinfo.go on linux

make testfile path relative to support fork work

pkg/s3select/select_test.go

@@ -18,12 +18,10 @@ package s3select
 
 import (
 	"bytes"
-	"go/build"
 	"io"
 	"io/ioutil"
 	"net/http"
 	"os"
-	"path"
 	"reflect"
 	"testing"
 )
@@ -174,7 +172,7 @@ func TestParquetInput(t *testing.T) {
 `)
 
 	getReader := func(offset int64, length int64) (io.ReadCloser, error) {
-		testdataFile := path.Join(build.Default.GOPATH, "src/github.com/minio/minio/pkg/s3select/testdata.parquet")
+		testdataFile := "testdata.parquet"
 		file, err := os.Open(testdataFile)
 		if err != nil {
 			return nil, err