This is more of a hack but looks like the best we can do.
The reason for this is the following:
1/ we require strict mode for our v4 script
2/ v0.10 in strict mode marks 'let' as a reserved keyword,
aborting before execution any code in the script. Thus,
we can't assert e.g. on process.versions['node'] !== '4'.
Daniel J. Hofmann
41d0f42ddf