Goop 1.2.0

Lang embeds: hard-break rename to import go / @[go], plus cgo-shaped @[c].

Highlights

Breaking: import golang, @golang, and the golang keyword are removed — use import go and @[go]
@[c]: inline C via cgo (preamble + import "C" + primitive val wrappers)
Docs: 15-lang-embeds.md, tutorial interop chapter, cgo_demo.goop
Tests: c_embed_* e2e; renamed import_go / go_embed; TextMate scopes for @[go] / @[c]