Minor fixes to make some tests build and run (#752)

* cmd/dlv: fall back to go env GOPATH when GOPATH envvar is unset.

Since Go 1.8, GOPATH environment variable has a default value if the
environment variable is unset so not setting GOPATH is perfectly ok.
Depend on `go env` command to query Go related environment variable.

* build: update references to moved packages

Makefile

@@ -68,4 +68,4 @@ test-proc-run:
 	go test $(TEST_FLAGS) $(BUILD_FLAGS) -test.v -test.run="$(RUN)" $(PREFIX)/pkg/proc
 
 test-integration-run:
-	go test $(TEST_FLAGS) $(BUILD_FLAGS) -test.run="$(RUN)" $(PREFIX)/pkg/service/test
+	go test $(TEST_FLAGS) $(BUILD_FLAGS) -test.run="$(RUN)" $(PREFIX)/service/test

cmd/dlv/dlv_test.go

@@ -6,6 +6,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"runtime"
+	"strings"
 	"testing"
 
 	protest "github.com/derekparker/delve/pkg/proc/test"
@@ -20,9 +21,20 @@ func assertNoError(err error, t testing.TB, s string) {
 	}
 }
 
+func goEnv(name string) string {
+	if val := os.Getenv(name); val != "" {
+		return val
+	}
+	val, err := exec.Command("go", "env", name).Output()
+	if err != nil {
+		panic(err) // the Go tool was tested to work earlier
+	}
+	return strings.TrimSpace(string(val))
+}
+
 func TestBuild(t *testing.T) {
 	const listenAddr = "localhost:40573"
-	makefilepath := filepath.Join(os.Getenv("GOPATH"), "src", "github.com", "derekparker", "delve", "Makefile")
+	makefilepath := filepath.Join(goEnv("GOPATH"), "src", "github.com", "derekparker", "delve", "Makefile")
 	t.Logf("makefile: %q", makefilepath)
 	var err error
 	for _, make := range []string{"make", "mingw32-make"} {

scripts/gen-cli-docs.go

@@ -5,7 +5,7 @@ import (
 	"log"
 	"os"
 
-	"github.com/derekparker/delve/terminal"
+	"github.com/derekparker/delve/pkg/terminal"
 )
 
 func main() {