Broken symlinks in lndir build tree

I routinely create separate build trees using lndir (per wiki:WorkingConventions/Git#Creatingabuildtreewithlndir). However it seems this is currently broken by the code to copy fs.{c,h} to various places in ./configure (see D4416):

$ mkdir ghc-validate
$ cd ghc-validate
$ lndir ../ghc
$ ln -s ../ghc/.git
$ ./boot
[...]
$ ./configure
[...]
$ find . -name "fs.*" | xargs file
./rts/fs.c:                    broken symbolic link to ../../../ghc/utils/fs/fs.c
./rts/fs.h:                    broken symbolic link to ../../../ghc/utils/fs/fs.h
./utils/fs/fs.c:               symbolic link to ../../../ghc/utils/fs/fs.c
./utils/fs/fs.h:               symbolic link to ../../../ghc/utils/fs/fs.h
./utils/unlit/fs.c:            symbolic link to ../../../ghc/utils/fs/fs.c
./utils/unlit/fs.h:            symbolic link to ../../../ghc/utils/fs/fs.h
./utils/lndir/fs.c:            symbolic link to ../../../ghc/utils/fs/fs.c
./utils/lndir/fs.h:            symbolic link to ../../../ghc/utils/fs/fs.h
./libraries/base/include/fs.h: broken symbolic link to ../../../ghc/utils/fs/fs.h
./libraries/base/cbits/fs.c:   broken symbolic link to ../../../ghc/utils/fs/fs.c

This can be fixed by manually correcting the symlinks, but it is a bit of pain, especially for ./validate.

ln -fs ../../ghc/utils/fs/fs.c rts/fs.c
ln -fs ../../ghc/utils/fs/fs.h rts/fs.h
ln -fs ../../../../ghc/utils/fs/fs.c libraries/base/include/fs.c
ln -fs ../../../../ghc/utils/fs/fs.h libraries/base/include/fs.h
ln -fs ../../../../ghc/utils/fs/fs.c libraries/base/cbits/fs.c

Trac metadata

Trac field	Value
Version	8.5
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Build System
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed milestone to %8.6.1

changed weight to 5

added Tbug Trac import labels

Trac metadata

Trac field	Value
Differential revisions	- → D4853

mentioned in commit 8ee9c574

closed

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

reopened

Unfortunately the fix broke the build on OS X, as ln -L is not supported (see d55035f5).

Trac metadata

Trac field	Value
Resolution	ResolvedFixed → Unresolved

changed milestone to %8.8.1

These won't be addressed in GHC 8.6.

The new Hadrian build system has been merged. Relabeling the tickets concerning the legacy make build system to prevent confusion.

Trac metadata

Trac field	Value
Component	Build System → Build System (make)

changed milestone to %8.10.1

Bumping milestones of low-priority tickets.

added ghc build failure label

added Pnormal label

removed milestone