commands: use buildx env for experimental opt-in

[tonistiigi]

I messed this up when doing the final review edits for #1100

Signed-off-by: Tonis Tiigi tonistiigi@gmail.com

[crazy-max]

Missed

buildx/commands/build.go

Line 704 in da1f4b8

if v, ok := os.LookupEnv("BUILDKIT_EXPERIMENTAL"); ok {

Also don't think we need to say BUILDX_EXPERIMENTAL=1 is required. for this flag as it's hidden behind the isExperimental() cond anyway.

[jedevc]

Woops, we should definitely be consistent with keeping BUILDX_EXPERIMENTAL=1 is required. between --invoke and --print. I think some sort of (experimental) note after both would be nice though - just to indicate that it has been activated with the isExperimental condition.

[crazy-max]

@jedevc Sgtm