feat: Host environment (#1293)

pkg/lookpath/env.go

@@ -0,0 +1,18 @@
+package lookpath
+
+import "os"
+
+type Env interface {
+	Getenv(name string) string
+}
+
+type defaultEnv struct {
+}
+
+func (*defaultEnv) Getenv(name string) string {
+	return os.Getenv(name)
+}
+
+func LookPath(file string) (string, error) {
+	return LookPath2(file, &defaultEnv{})
+}