Merge branch 'hacking'

_CoqProject

theories/lang/adequacy.v

theories/lang/derived.v

theories/lang/heap.v

theories/lang/lang.v

theories/lang/lifting.v

theories/lang/memcpy.v

theories/lang/notation.v

theories/lang/proofmode.v

theories/lang/races.v

theories/lang/tactics.v

theories/lang/wp_tactics.v

theories/lft_contexts.v

theories/lifetime.v

theories/lifetime/accessors.v

theories/lifetime/borrow.v

theories/lifetime/creation.v

theories/lifetime/definitions.v

theories/lifetime/derived.v

theories/lifetime/frac_borrow.v