Segfault in RSAGL with +RTS -G4

[Christopher Lane Hinson]

I regret that I don't have a simpler failure case, but I'm just going to 
post this and please advise me.  I don't see how to get debugging symbols 
to work to even look at a core dump.

Usually I get a segfault, but sometimes I get this:

_rsagl_modelview: internal error: evacuate: strange closure type 2053
     (GHC version 6.10.1 for i386_unknown_linux)
     Please report this as a GHC bug: 
http://www.haskell.org/ghc/reportabug
Aborted

This program uses ffi, but in this checkin I've disabled RSAGL's ffi 
except the GLUT+OpenGL bindings.  So it's OpenGL or ghc.

The key to getting this error is the -G flag.  -G4 or -G3 segfaults.

Steps to replicate:

git clone http://www.downstairspeople.org/git/rsagl.git
cd rsagl/
git checkout possible_rts_bug_g4
cabal configure && cabal build
./dist/build/_rsagl_modelview/_rsagl_modelview +RTS -G4 -RTS
<-- just sit and wait, it should display an animation briefly and then 
segfault.

Friendly,
--Lane