Add flag to configure that skips overwriting of symlinks on install

Sometimes when I'm installing a GHC release candidates I'd like to install the RC without overwriting the ghc etc symlinks in /usr/local/bin. It would be convenient to have a configure flag that told the install step to only install the versioned binaries (e.g. ghc-6.2.1) in /usr/local/bin, without the symlinks.

Trac metadata

Trac field	Value
Version	7.4.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Build System
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed weight to 5

added Tbug Trac import labels

changed milestone to %7.8.1

changed weight to 7

I like this idea too.

Trac metadata

Trac field	Value
Priority	normal → high

I install different versions to /usr/local/ghc/ghc-x.y.z and have a bunch of bash functions/aliases that prepend the selected version to $PATH &c.

If we're going to allow multiple versioned binaries to be installed directly to /usr (which would be nice), we'll want some way to choose between them too, cf. gcc_select on OS X, in which case we should also figure out how that'd interact with say Debian's update-alternatives(8).

Trac metadata

Trac field	Value
CC	→ hackage.haskell.org@liyang.hu

assigned to @trac-thoughtpolice

I'll look into this for 7.8.1. I agree we should maybe have some gcc_select style thing, but I don't quite know how these works or the details of Debian's approach, so I may just do the simple thing first and come back to that.

changed milestone to %7.10.1

Bumping priority down (these tickets haven't been closely followed or fixed in 7.4), and moving out to 7.10 and out of 7.8.3.

changed weight to 5

Actually dropping priority. :)

Trac metadata

Trac field	Value
Priority	high → normal

Trac metadata

Trac field	Value
Type	Bug → FeatureRequest

removed milestone

Moving to 7.12.1 milestone; if you feel this is an error and should be addressed sooner, please move it back to the 7.10.1 milestone.

See also this thread: https://mail.haskell.org/pipermail/glasgow-haskell-users/2015-July/026020.html "simultaneous ghc versions", which concluded with:

Come to think of it, shouldn't ghc include this, instead of everyone creating their own shell scripts by hand?

I don't think so. This is usually done in the userland -- at least in GNU+Linux distributions.

More to the point, various distribution methods already include such things (e.g. NixOS, Debian's alternatives system, MacPorts' "port select") plus there are various mechanisms for implementing this on an ad-hoc basis (GNU stow, environment modules, etc.). Downstream packages implementing their own versions of this except speicifically on an opt-in basis (e.g. configure option) tend to interfere with these and complicate inclusion into existing package systems.

changed milestone to %8.0.1

Milestone renamed

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)

added Pnormal label