nixpkgs/pkgs/development/haskell-modules/configuration-nix.nix

499 lines
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Nix

# NIX-SPECIFIC OVERRIDES/PATCHES FOR HASKELL PACKAGES
#
# This file contains overrides which are needed because of Nix. For example,
# some packages may need help finding the location of native libraries. In
# general, overrides in this file are (mostly) due to one of the following reasons:
#
# * packages that hard code the location of native libraries, so they need to be patched/
# supplied the patch explicitly
# * passing native libraries that are not detected correctly by cabal2nix
# * test suites that fail due to some features not available in the nix sandbox
# (networking being a common one)
#
# In general, this file should *not* contain overrides that fix build failures that could
# also occur on standard, FHS-compliant non-Nix systems. For example, if tests have a compile
# error, that is a bug in the package, and that failure has nothing to do with Nix.
#
# Common examples which should *not* be a part of this file:
#
# * overriding a specific version of a haskell library because some package fails
# to build with a newer version. Such overrides have nothing to do with Nix itself,
# and they would also be neccessary outside of Nix if you use the same set of
# package versions.
# * disabling tests that fail due to missing files in the tarball or compile errors
# * disabling tests that require too much memory
# * enabling/disabling certain features in packages
#
# If you have an override of this kind, see configuration-common.nix instead.
{ pkgs, haskellLib }:
with haskellLib;
# All of the overrides in this set should look like:
#
# foo = ... something involving super.foo ...
#
# but that means that we add `foo` attribute even if there is no `super.foo`! So if
# you want to use this configuration for a package set that only contains a subset of
# the packages that have overrides defined here, you'll end up with a set that contains
# a bunch of attributes that trigger an evaluation error.
#
# To avoid this, we use `intersectAttrs` here so we never add packages that are not present
# in the parent package set (`super`).
self: super: builtins.intersectAttrs super {
# Apply NixOS-specific patches.
ghc-paths = appendPatch super.ghc-paths ./patches/ghc-paths-nix.patch;
# fix errors caused by hardening flags
epanet-haskell = disableHardening super.epanet-haskell ["format"];
# Link the proper version.
zeromq4-haskell = super.zeromq4-haskell.override { zeromq = pkgs.zeromq4; };
# Use the default version of mysql to build this package (which is actually mariadb).
# test phase requires networking
mysql = dontCheck (super.mysql.override { mysql = pkgs.mysql.lib; });
# CUDA needs help finding the SDK headers and libraries.
cuda = overrideCabal super.cuda (drv: {
extraLibraries = (drv.extraLibraries or []) ++ [pkgs.linuxPackages.nvidia_x11];
configureFlags = (drv.configureFlags or []) ++
pkgs.lib.optional pkgs.stdenv.is64bit "--extra-lib-dirs=${pkgs.cudatoolkit}/lib64" ++ [
"--extra-lib-dirs=${pkgs.cudatoolkit}/lib"
"--extra-include-dirs=${pkgs.cudatoolkit}/include"
];
preConfigure = ''
export CUDA_PATH=${pkgs.cudatoolkit}
'';
});
nvvm = overrideCabal super.nvvm (drv: {
preConfigure = ''
export CUDA_PATH=${pkgs.cudatoolkit}
'';
});
cufft = overrideCabal super.cufft (drv: {
preConfigure = ''
export CUDA_PATH=${pkgs.cudatoolkit}
'';
});
# jni needs help finding libjvm.so because it's in a weird location.
jni = overrideCabal super.jni (drv: {
preConfigure = ''
local libdir=( "${pkgs.jdk}/lib/openjdk/jre/lib/"*"/server" )
configureFlags+=" --extra-lib-dir=''${libdir[0]}"
'';
});
# The package doesn't know about the AL include hierarchy.
# https://github.com/phaazon/al/issues/1
al = appendConfigureFlag super.al "--extra-include-dirs=${pkgs.openal}/include/AL";
# Won't find it's header files without help.
sfml-audio = appendConfigureFlag super.sfml-audio "--extra-include-dirs=${pkgs.openal}/include/AL";
hzk = overrideCabal super.hzk (drv: {
preConfigure = "sed -i -e /include-dirs/d hzk.cabal";
configureFlags = "--extra-include-dirs=${pkgs.zookeeper_mt}/include/zookeeper";
});
haskakafka = overrideCabal super.haskakafka (drv: {
preConfigure = "sed -i -e /extra-lib-dirs/d -e /include-dirs/d haskakafka.cabal";
configureFlags = "--extra-include-dirs=${pkgs.rdkafka}/include/librdkafka";
});
# library has hard coded directories that need to be removed. Reported upstream here https://github.com/haskell-works/hw-kafka-client/issues/32
hw-kafka-client = dontCheck (overrideCabal super.hw-kafka-client (drv: {
preConfigure = "sed -i -e /extra-lib-dirs/d -e /include-dirs/d -e /librdkafka/d hw-kafka-client.cabal";
configureFlags = "--extra-include-dirs=${pkgs.rdkafka}/include/librdkafka";
}));
# Foreign dependency name clashes with another Haskell package.
libarchive-conduit = super.libarchive-conduit.override { archive = pkgs.libarchive; };
# Fix Darwin build.
halive = if pkgs.stdenv.isDarwin
then addBuildDepend super.halive pkgs.darwin.apple_sdk.frameworks.AppKit
else super.halive;
# Heist's test suite requires system pandoc
heist = overrideCabal super.heist (drv: {
testToolDepends = [pkgs.pandoc];
});
# the system-fileio tests use canonicalizePath, which fails in the sandbox
system-fileio = if pkgs.stdenv.isDarwin then dontCheck super.system-fileio else super.system-fileio;
# Prevents needing to add security_tool as a build tool to all of x509-system's
# dependencies.
x509-system = if pkgs.stdenv.isDarwin && !pkgs.stdenv.cc.nativeLibc
then let inherit (pkgs.darwin) security_tool;
in pkgs.lib.overrideDerivation (addBuildDepend super.x509-system security_tool) (drv: {
postPatch = (drv.postPatch or "") + ''
substituteInPlace System/X509/MacOS.hs --replace security ${security_tool}/bin/security
'';
})
else super.x509-system;
# https://github.com/NixOS/cabal2nix/issues/136 and https://github.com/NixOS/cabal2nix/issues/216
gio = disableHardening (addPkgconfigDepend (addBuildTool super.gio self.gtk2hs-buildtools) pkgs.glib) ["fortify"];
glib = disableHardening (addPkgconfigDepend (addBuildTool super.glib self.gtk2hs-buildtools) pkgs.glib) ["fortify"];
gtk3 = disableHardening (super.gtk3.override { inherit (pkgs) gtk3; }) ["fortify"];
gtk = disableHardening (addPkgconfigDepend (addBuildTool super.gtk self.gtk2hs-buildtools) pkgs.gtk2) ["fortify"];
gtksourceview2 = addPkgconfigDepend super.gtksourceview2 pkgs.gtk2;
# Need WebkitGTK, not just webkit.
webkit = super.webkit.override { webkit = pkgs.webkitgtk24x-gtk2; };
websnap = super.websnap.override { webkit = pkgs.webkitgtk24x-gtk3; };
hs-mesos = overrideCabal super.hs-mesos (drv: {
# Pass _only_ mesos; the correct protobuf is propagated.
extraLibraries = [ pkgs.mesos ];
preConfigure = "sed -i -e /extra-lib-dirs/d -e 's|, /usr/include, /usr/local/include/mesos||' hs-mesos.cabal";
});
# These packages try to access the network.
amqp = dontCheck super.amqp;
amqp-conduit = dontCheck super.amqp-conduit;
bitcoin-api = dontCheck super.bitcoin-api;
bitcoin-api-extra = dontCheck super.bitcoin-api-extra;
bitx-bitcoin = dontCheck super.bitx-bitcoin; # http://hydra.cryp.to/build/926187/log/raw
concurrent-dns-cache = dontCheck super.concurrent-dns-cache;
digitalocean-kzs = dontCheck super.digitalocean-kzs; # https://github.com/KazumaSATO/digitalocean-kzs/issues/1
github-types = dontCheck super.github-types; # http://hydra.cryp.to/build/1114046/nixlog/1/raw
hadoop-rpc = dontCheck super.hadoop-rpc; # http://hydra.cryp.to/build/527461/nixlog/2/raw
hasql = dontCheck super.hasql; # http://hydra.cryp.to/build/502489/nixlog/4/raw
hasql-transaction = dontCheck super.hasql-transaction; # wants to connect to postgresql
hjsonschema = overrideCabal super.hjsonschema (drv: { testTarget = "local"; });
marmalade-upload = dontCheck super.marmalade-upload; # http://hydra.cryp.to/build/501904/nixlog/1/raw
mongoDB = dontCheck super.mongoDB;
network-transport-tcp = dontCheck super.network-transport-tcp;
network-transport-zeromq = dontCheck super.network-transport-zeromq; # https://github.com/tweag/network-transport-zeromq/issues/30
pipes-mongodb = dontCheck super.pipes-mongodb; # http://hydra.cryp.to/build/926195/log/raw
raven-haskell = dontCheck super.raven-haskell; # http://hydra.cryp.to/build/502053/log/raw
riak = dontCheck super.riak; # http://hydra.cryp.to/build/498763/log/raw
scotty-binding-play = dontCheck super.scotty-binding-play;
servant-router = dontCheck super.servant-router;
serversession-backend-redis = dontCheck super.serversession-backend-redis;
slack-api = dontCheck super.slack-api; # https://github.com/mpickering/slack-api/issues/5
socket = dontCheck super.socket;
stackage = dontCheck super.stackage; # http://hydra.cryp.to/build/501867/nixlog/1/raw
textocat-api = dontCheck super.textocat-api; # http://hydra.cryp.to/build/887011/log/raw
warp = dontCheck super.warp; # http://hydra.cryp.to/build/501073/nixlog/5/raw
wreq = dontCheck super.wreq; # http://hydra.cryp.to/build/501895/nixlog/1/raw
wreq-sb = dontCheck super.wreq-sb; # http://hydra.cryp.to/build/783948/log/raw
wuss = dontCheck super.wuss; # http://hydra.cryp.to/build/875964/nixlog/2/raw
download = dontCheck super.download;
http-client = dontCheck super.http-client;
http-client-openssl = dontCheck super.http-client-openssl;
http-client-tls = dontCheck super.http-client-tls;
http-conduit = dontCheck super.http-conduit;
transient-universe = dontCheck super.transient-universe;
typed-process = dontCheck super.typed-process;
js-jquery = dontCheck super.js-jquery;
hPDB-examples = dontCheck super.hPDB-examples;
configuration-tools = dontCheck super.configuration-tools; # https://github.com/alephcloud/hs-configuration-tools/issues/40
tcp-streams = dontCheck super.tcp-streams;
holy-project = dontCheck super.holy-project;
mustache = dontCheck super.mustache;
# Tries to mess with extended POSIX attributes, but can't in our chroot environment.
xattr = dontCheck super.xattr;
# Needs access to locale data, but looks for it in the wrong place.
scholdoc-citeproc = dontCheck super.scholdoc-citeproc;
# Expect to find sendmail(1) in $PATH.
mime-mail = appendConfigureFlag super.mime-mail "--ghc-option=-DMIME_MAIL_SENDMAIL_PATH=\"sendmail\"";
# Help the test suite find system timezone data.
tz = overrideCabal super.tz (drv: { preConfigure = "export TZDIR=${pkgs.tzdata}/share/zoneinfo"; });
# Nix-specific workaround
xmonad = appendPatch (dontCheck super.xmonad) ./patches/xmonad-nix.patch;
# wxc supports wxGTX >= 3.0, but our current default version points to 2.8.
# http://hydra.cryp.to/build/1331287/log/raw
wxc = (addBuildDepend super.wxc self.split).override { wxGTK = pkgs.wxGTK30; };
wxcore = super.wxcore.override { wxGTK = pkgs.wxGTK30; };
# Test suite wants to connect to $DISPLAY.
hsqml = dontCheck (addExtraLibrary (super.hsqml.override { qt5 = pkgs.qt5Full; }) pkgs.mesa);
# Tests attempt to use NPM to install from the network into
# /homeless-shelter. Disabled.
purescript = dontCheck super.purescript;
# Hardcoded include path
poppler = overrideCabal super.poppler (drv: {
postPatch = ''
sed -i -e 's,glib/poppler.h,poppler.h,' poppler.cabal
sed -i -e 's,glib/poppler.h,poppler.h,' Graphics/UI/Gtk/Poppler/Structs.hsc
'';
});
# Uses OpenGL in testing
caramia = dontCheck super.caramia;
llvm-general =
# Supports only 3.5 for now, https://github.com/bscarlet/llvm-general/issues/142
let base = super.llvm-general.override { llvm-config = pkgs.llvm_35; };
in if !pkgs.stdenv.isDarwin then base else overrideCabal base (
drv: {
preConfigure = ''
sed -i llvm-general.cabal \
-e 's,extra-libraries: stdc++,extra-libraries: c++,'
'';
configureFlags = (drv.configureFlags or []) ++ ["--extra-include-dirs=${pkgs.libcxx}/include/c++/v1"];
librarySystemDepends = [ pkgs.libcxx ] ++ drv.librarySystemDepends or [];
}
);
llvm-hs = super.llvm-hs.override { llvm-config = pkgs.llvm_4; };
# Needs help finding LLVM.
spaceprobe = addBuildTool super.spaceprobe self.llvmPackages.llvm;
# Tries to run GUI in tests
leksah = dontCheck (overrideCabal super.leksah (drv: {
executableSystemDepends = (drv.executableSystemDepends or []) ++ (with pkgs; [
gnome3.defaultIconTheme # Fix error: Icon 'window-close' not present in theme ...
wrapGAppsHook # Fix error: GLib-GIO-ERROR **: No GSettings schemas are installed on the system
gtk3 # Fix error: GLib-GIO-ERROR **: Settings schema 'org.gtk.Settings.FileChooser' is not installed
]);
postPatch = (drv.postPatch or "") + ''
for f in src/IDE/Leksah.hs src/IDE/Utils/ServerConnection.hs
do
substituteInPlace "$f" --replace "\"leksah-server\"" "\"${self.leksah-server}/bin/leksah-server\""
done
'';
}));
# Patch to consider NIX_GHC just like xmonad does
dyre = appendPatch super.dyre ./patches/dyre-nix.patch;
yesod-bin = if pkgs.stdenv.isDarwin
then addBuildDepend super.yesod-bin pkgs.darwin.apple_sdk.frameworks.Cocoa
else super.yesod-bin;
hmatrix = if pkgs.stdenv.isDarwin
then addBuildDepend super.hmatrix pkgs.darwin.apple_sdk.frameworks.Accelerate
else super.hmatrix;
# https://github.com/edwinb/EpiVM/issues/13
# https://github.com/edwinb/EpiVM/issues/14
epic = addExtraLibraries (addBuildTool super.epic self.happy) [pkgs.boehmgc pkgs.gmp];
# https://github.com/ekmett/wl-pprint-terminfo/issues/7
wl-pprint-terminfo = addExtraLibrary super.wl-pprint-terminfo pkgs.ncurses;
# https://github.com/bos/pcap/issues/5
pcap = addExtraLibrary super.pcap pkgs.libpcap;
# The cabal files for these libraries do not list the required system dependencies.
miniball = overrideCabal super.miniball (drv: {
librarySystemDepends = [ pkgs.miniball ];
});
SDL-image = overrideCabal super.SDL-image (drv: {
librarySystemDepends = [ pkgs.SDL pkgs.SDL_image ] ++ drv.librarySystemDepends or [];
});
SDL-ttf = overrideCabal super.SDL-ttf (drv: {
librarySystemDepends = [ pkgs.SDL pkgs.SDL_ttf ];
});
SDL-mixer = overrideCabal super.SDL-mixer (drv: {
librarySystemDepends = [ pkgs.SDL pkgs.SDL_mixer ];
});
SDL-gfx = overrideCabal super.SDL-gfx (drv: {
librarySystemDepends = [ pkgs.SDL pkgs.SDL_gfx ];
});
SDL-mpeg = overrideCabal super.SDL-mpeg (drv: {
configureFlags = (drv.configureFlags or []) ++ [
"--extra-lib-dirs=${pkgs.smpeg}/lib"
"--extra-include-dirs=${pkgs.smpeg}/include/smpeg"
];
});
# https://github.com/ivanperez-keera/hcwiid/pull/4
hcwiid = overrideCabal super.hcwiid (drv: {
configureFlags = (drv.configureFlags or []) ++ [
"--extra-lib-dirs=${pkgs.bluez.out}/lib"
"--extra-lib-dirs=${pkgs.cwiid}/lib"
"--extra-include-dirs=${pkgs.cwiid}/include"
"--extra-include-dirs=${pkgs.bluez.dev}/include"
];
prePatch = '' sed -i -e "/Extra-Lib-Dirs/d" -e "/Include-Dirs/d" "hcwiid.cabal" '';
});
# cabal2nix doesn't pick up some of the dependencies.
ginsu = let
g = addBuildDepend super.ginsu pkgs.perl;
g' = overrideCabal g (drv: {
executableSystemDepends = (drv.executableSystemDepends or []) ++ [
pkgs.ncurses
];
});
in g';
# Tests require `docker` command in PATH
# Tests require running docker service :on localhost
docker = dontCheck super.docker;
# https://github.com/deech/fltkhs/issues/16
fltkhs = overrideCabal super.fltkhs (drv: {
libraryToolDepends = (drv.libraryToolDepends or []) ++ [pkgs.autoconf];
librarySystemDepends = (drv.librarySystemDepends or []) ++ [pkgs.fltk13 pkgs.mesa_noglu pkgs.libjpeg];
});
# https://github.com/skogsbaer/hscurses/pull/26
hscurses = overrideCabal super.hscurses (drv: {
librarySystemDepends = (drv.librarySystemDepends or []) ++ [ pkgs.ncurses ];
});
# Looks like Avahi provides the missing library
dnssd = super.dnssd.override { dns_sd = pkgs.avahi.override { withLibdnssdCompat = true; }; };
# Ensure the necessary frameworks are propagatedBuildInputs on darwin
OpenGLRaw = overrideCabal super.OpenGLRaw (drv: {
librarySystemDepends =
pkgs.lib.optionals (!pkgs.stdenv.isDarwin) drv.librarySystemDepends;
libraryHaskellDepends = drv.libraryHaskellDepends
++ pkgs.lib.optionals pkgs.stdenv.isDarwin
[ pkgs.darwin.apple_sdk.frameworks.OpenGL ];
preConfigure = pkgs.lib.optionalString pkgs.stdenv.isDarwin ''
frameworkPaths=($(for i in $nativeBuildInputs; do if [ -d "$i"/Library/Frameworks ]; then echo "-F$i/Library/Frameworks"; fi done))
frameworkPaths=$(IFS=, ; echo "''${frameworkPaths[@]}")
configureFlags+=$(if [ -n "$frameworkPaths" ]; then echo -n "--ghc-options=-optl=$frameworkPaths"; fi)
'';
});
GLURaw = overrideCabal super.GLURaw (drv: {
librarySystemDepends =
pkgs.lib.optionals (!pkgs.stdenv.isDarwin) drv.librarySystemDepends;
libraryHaskellDepends = drv.libraryHaskellDepends
++ pkgs.lib.optionals pkgs.stdenv.isDarwin
[ pkgs.darwin.apple_sdk.frameworks.OpenGL ];
});
bindings-GLFW = overrideCabal super.bindings-GLFW (drv: {
doCheck = false; # requires an active X11 display
librarySystemDepends =
pkgs.lib.optionals (!pkgs.stdenv.isDarwin) drv.librarySystemDepends;
libraryHaskellDepends = drv.libraryHaskellDepends
++ pkgs.lib.optionals pkgs.stdenv.isDarwin
(with pkgs.darwin.apple_sdk.frameworks;
[ AGL Cocoa OpenGL IOKit Kernel CoreVideo
pkgs.darwin.CF ]);
});
OpenCL = overrideCabal super.OpenCL (drv: {
librarySystemDepends =
pkgs.lib.optionals (!pkgs.stdenv.isDarwin) drv.librarySystemDepends;
libraryHaskellDepends = drv.libraryHaskellDepends
++ pkgs.lib.optionals pkgs.stdenv.isDarwin
[ pkgs.darwin.apple_sdk.frameworks.OpenCL ];
});
# GLUT uses `dlopen` to link to freeglut, so we need to set the RUNPATH correctly for
# it to find `libglut.so` from the nix store. We do this by patching GLUT.cabal to pkg-config
# depend on freeglut, which provides GHC to necessary information to generate a correct RPATH.
#
# Note: Simply patching the dynamic library (.so) of the GLUT build will *not* work, since the
# RPATH also needs to be propagated when using static linking. GHC automatically handles this for
# us when we patch the cabal file (Link options will be recored in the ghc package registry).
#
# Additional note: nixpkgs' freeglut and macOS's OpenGL implementation do not cooperate,
# so disable this on Darwin only
${if pkgs.stdenv.isDarwin then null else "GLUT"} = addPkgconfigDepend (appendPatch super.GLUT ./patches/GLUT.patch) pkgs.freeglut;
idris = overrideCabal super.idris (drv: {
# https://github.com/idris-lang/Idris-dev/issues/2499
librarySystemDepends = (drv.librarySystemDepends or []) ++ [pkgs.gmp];
# tests and build run executable, so need to set LD_LIBRARY_PATH
preBuild = ''
export LD_LIBRARY_PATH="$PWD/dist/build:$LD_LIBRARY_PATH"
'';
});
libsystemd-journal = overrideCabal super.libsystemd-journal (old: {
librarySystemDepends = old.librarySystemDepends or [] ++ [ pkgs.systemd ];
});
# does not specify tests in cabal file, instead has custom runTest cabal hook,
# so cabal2nix will not detect test dependencies.
either-unwrap = overrideCabal super.either-unwrap (drv: {
testHaskellDepends = (drv.testHaskellDepends or []) ++ [ self.test-framework self.test-framework-hunit ];
});
# cabal2nix likes to generate dependencies on hinotify when hfsevents is really required
# on darwin: https://github.com/NixOS/cabal2nix/issues/146.
hinotify = if pkgs.stdenv.isDarwin then self.hfsevents else super.hinotify;
# FSEvents API is very buggy and tests are unreliable. See
# http://openradar.appspot.com/10207999 and similar issues.
# https://github.com/haskell-fswatch/hfsnotify/issues/62
fsnotify = if pkgs.stdenv.isDarwin
then addBuildDepend (dontCheck super.fsnotify) pkgs.darwin.apple_sdk.frameworks.Cocoa
else dontCheck super.fsnotify;
hidapi = addExtraLibrary super.hidapi pkgs.libudev;
hs-GeoIP = super.hs-GeoIP.override { GeoIP = pkgs.geoipWithDatabase; };
discount = super.discount.override { markdown = pkgs.discount; };
# tests require working stack installation with all-cabal-hashes cloned in $HOME
stackage-curator = dontCheck super.stackage-curator;
# hardcodes /usr/bin/tr: https://github.com/snapframework/io-streams/pull/59
io-streams = enableCabalFlag super.io-streams "NoInteractiveTests";
# requires autotools to build
secp256k1 = addBuildTools super.secp256k1 [ pkgs.autoconf pkgs.automake pkgs.libtool ];
# tests require git
hapistrano = addBuildTool super.hapistrano pkgs.git;
# This propagates this to everything depending on haskell-gi-base
haskell-gi-base = addBuildDepend super.haskell-gi-base pkgs.gobjectIntrospection;
# Requires gi-javascriptcore API version 4
gi-webkit2 = super.gi-webkit2.override { gi-javascriptcore = self.gi-javascriptcore_4_0_14; };
# requires valid, writeable $HOME
hatex-guide = overrideCabal super.hatex-guide (drv: {
preConfigure = ''
${drv.preConfigure or ""}
export HOME=$PWD
'';
});
# Fails to link against with newer gsl versions because a deprecrated function
# was removed
hmatrix-gsl = super.hmatrix-gsl.override { gsl = pkgs.gsl_1; };
# tests run executable, relying on PATH
# without this, tests fail with "Couldn't launch intero process"
intero = overrideCabal super.intero (drv: {
preCheck = ''
export PATH="$PWD/dist/build/intero:$PATH"
'';
});
# loc and loc-test depend on each other for testing. Break that infinite cycle:
loc-test = super.loc-test.override { loc = dontCheck self.loc; };
# The test suites try to run the "fixpoint" and "liquid" executables built just
# before and fail because the library search paths aren't configured properly.
# Also needs https://github.com/ucsd-progsys/liquidhaskell/issues/1038 resolved.
liquid-fixpoint = disableSharedExecutables super.liquid-fixpoint;
liquidhaskell = dontCheck (disableSharedExecutables super.liquidhaskell);
# Haskell OpenCV bindings need contrib code enabled in the C++ library.
opencv = super.opencv.override { opencv3 = pkgs.opencv3.override { enableContrib = true; }; };
# Without this override, the builds lacks pkg-config.
opencv-extra = addPkgconfigDepend super.opencv-extra (pkgs.opencv3.override { enableContrib = true; });
}