Mysterious segfault with custom Setup.hs

Idris's setup program [started segfaulting recently](https://github.com/idris-lang/Idris-dev/pull/3456#issuecomment-255614643). I'm quite baffled as to what's going on here—the only thing I can say for sure is that a custom `Setup.hs` is definitely required to trigger this bug. I have a [`cabal-gh4367`](https://github.com/RyanGlScott/cabal-gh4367) repo which attempts to minimize the steps needed to reproduce the error. You can see the segfault happen yourself on [this most recent Travis run](https://travis-ci.org/RyanGlScott/cabal-gh4367/builds/214669100). Note that it happens on every version of GHC except for GHC 8.0.2, for some reason.

Here's an excerpt from the [GHC 7.10.3 run](https://travis-ci.org/RyanGlScott/cabal-gh4367/jobs/214669103#L282):

```
$ cabal configure --enable-tests --enable-benchmarks -v2
/opt/ghc/7.10.3/bin/ghc --numeric-version
looking for tool ghc-pkg near compiler in /opt/ghc/7.10.3/bin
found ghc-pkg in /opt/ghc/7.10.3/bin/ghc-pkg
/opt/ghc/7.10.3/bin/ghc-pkg --version
/opt/ghc/7.10.3/bin/ghc --supported-languages
/opt/ghc/7.10.3/bin/ghc --info
Reading available packages...
/usr/bin/pkg-config --version
/usr/bin/pkg-config --list-all
/usr/bin/pkg-config --modversion libtasn1 gio-unix-2.0 QtHelp zlib cairo-xcb QtOpenGL gio-2.0 libcdt QtNetwork QtTest libidn libpng12 cairo-gobject xinerama p11-kit-1 randrproto menu cairo-ps gmodule-2.0 IlmBase lcms QtDeclarative glib-2.0 xdmcp ImageMagick xau QtScriptTools libgraph pango MagickWand libdrm panelw gl libcgraph fontutil libpcrecpp pangoft2 ice QtCore libexslt libevent_pthreads libffi gmodule-no-export-2.0 pangox OpenEXR xrender gdk-pixbuf-2.0 libdrm_nouveau libxdot gdk-pixbuf-xlib-2.0 xext QtDesigner xcb QtSql pthread-stubs lqr-1 xproto 'gtk+-unix-print-2.0' python-2.7 QtUiTools renderproto gdk-2.0 menuw libssl librtmp yaml-0.1 ossp-uuid libevent openssl libxml-2.0 xi xrandr libevent_openssl cairo-pdf xcursor ncurses python xcomposite fixesproto xcb-shm xt QtXml pangocairo ddjvuapi gmodule-export-2.0 damageproto libgvpr dri x11 iso-codes xdamage libpq QtScript tinfo cairo-xlib QtDesignerComponents libdrm_nouveau1 sqlite3 'ncurses++w' 'gtk+-x11-2.0' pixman-1 compositeproto gnutls Qt3Support libpathplan QtDBus kbproto inputproto cairo-xcb-shm xextproto libdrm_radeon gobject-2.0 libgvc libpng gthread-2.0 cairo-fc fontconfig 'ncurses++' libcrypto python2 form com_err libcurl libpcreposix tic pangoxft cairo-xlib-xrender cairo-ft cairo cairo-png xft QtGui libmemcached libdrm_intel atk xkeyboard-config sm udisks xineramaproto glu cairo-svg QtWebKit ncursesw Wand QtXmlPatterns gnutls-extra xcb-render shared-mime-info panel gdk-x11-2.0 libpcre libexif autoopts xtrans freetype2 MagickCore formw xfixes udev QtSvg librsvg-2.0 'gtk+-2.0' QtCLucene xorg-sgml-doctools libxslt
Choosing modular solver.
Resolving dependencies...
creating dist/setup
creating dist
creating dist/setup
copy ./Setup.hs to ./dist/setup/setup.hs
/opt/ghc/7.10.3/bin/ghc --make -odir ./dist/setup -hidir ./dist/setup -i -i. -package-id Cabal-1.22.5.0-9ea569737527320f512dad57b36ee312 ./dist/setup/setup.hs -o ./dist/setup/setup -threaded
[1 of 1] Compiling Main ( dist/setup/setup.hs, dist/setup/Main.o )
Linking ./dist/setup/setup ...
./dist/setup/setup configure --verbose=2 --ghc --prefix=/home/travis/.cabal
--disable-library-profiling --disable-executable-profiling --user
--extra-prog-path=/home/travis/.cabal/bin
--dependency=array=array-0.5.1.0-960bf9ae8875cc30355e086f8853a049
--dependency=base=base-4.8.2.0-0d6d1084fbc041e1cded9228e80e264d
--dependency=binary=binary-0.7.5.0-5784fd031a720c3b84e73006e444c7ca
--dependency=bytestring=bytestring-0.10.6.0-c60f4c543b22c7f7293a06ae48820437
--dependency=containers=containers-0.5.6.2-e59c9b78d840fa743d4169d4bea15592
--dependency=deepseq=deepseq-1.4.1.1-614b63b36dd6e29d2b35afff57c25311
--dependency=directory=directory-1.3.1.1-GnluS50K3JJEl2Z38DQGUl
--dependency=filepath=filepath-1.4.0.0-f97d1e4aebfd7a03be6980454fe31d6e
--dependency=haskeline=haskeline-0.7.3.1-caebd446bbd40de5f68f6f6ebe1048c7
--dependency=pretty=pretty-1.1.2.0-5cc412214ea63f61ee84c4fbabdbe0ec
--dependency=time=time-1.5.0.1-edbd1a50e7922b396ada189ab8e8523b
--dependency=transformers=transformers-0.4.2.0-81450cd8f86b36eaa8fa0cbaf6efc3a3
--disable-tests --exact-configuration --disable-benchmarks
Configuring idris-0.12.3...
Dependency array ==0.5.1.0: using array-0.5.1.0
Dependency base ==4.8.2.0: using base-4.8.2.0
Dependency binary ==0.7.5.0: using binary-0.7.5.0
Dependency bytestring ==0.10.6.0: using bytestring-0.10.6.0
Dependency containers ==0.5.6.2: using containers-0.5.6.2
Dependency deepseq ==1.4.1.1: using deepseq-1.4.1.1
Dependency directory ==1.3.1.1: using directory-1.3.1.1
Dependency filepath ==1.4.0.0: using filepath-1.4.0.0
Dependency haskeline ==0.7.3.1: using haskeline-0.7.3.1
Dependency pretty ==1.1.2.0: using pretty-1.1.2.0
Dependency time ==1.5.0.1: using time-1.5.0.1
Dependency transformers ==0.4.2.0: using transformers-0.4.2.0
/home/travis/build.sh: line 62: 2629 Segmentation fault (core dumped) cabal configure --enable-tests --enable-benchmarks -v2
```

[Here's](https://github.com/RyanGlScott/cabal-gh4367/blob/ca692ba917c4a7edde07dc7c34ddcc6f676f2bb0/Setup.hs) the `Setup.hs` file in question. Nothing seems terribly out of the ordinary... do you have any idea what might be causing this?