Unable to build stage3 with hadrian

It seems that stage3 is unsupported by hadrian.

I am trying to build the target _build/stage2/bin/ghc but it is reported as an unknown program.

Trac metadata

Trac field	Value
Version	8.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed weight to 5

added Tbug Trac import labels

assigned to @mpickering

See D5458 for a patch which seems to get us most of the way there.

Trac metadata

Trac field	Value
Differential revisions	- → D5458

closed

Merged in 6486c6e4

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

added Pnormal label