.travis.yml: build for GHC 8.8.1

.travis.yml

@@ -406,3 +406,21 @@ matrix:
           --argstr compiler "ghc865"
         - nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/tarball/nixos-19.09 -p cachix --run 'cachix push ihaskell result'
         - test/acceptance.nbconvert.sh result/bin/ihaskell-nbconvert
+    - language: nix
+      dist: xenial
+      env: NIXPKGS_ALLOW_BROKEN=1
+      before_install:
+        - export NIX_CONF_DIR=~
+        - echo "binary-caches = https://cache.nixos.org https://ihaskell.cachix.org" >> $NIX_CONF_DIR/nix.conf
+        - echo "binary-cache-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= ihaskell.cachix.org-1:WoIvex/Ft/++sjYW3ntqPUL3jDGXIKDpX60pC8d5VLM=" >> $NIX_CONF_DIR/nix.conf
+        - glibcLocales=$(nix-build https://github.com/NixOS/nixpkgs-channels/tarball/nixos-19.09 -A glibcLocales)
+        - echo $glibcLocales
+        - export LOCALE_ARCHIVE_2_27="${glibcLocales}/lib/locale/locale-archive"
+      script:
+        - >
+          nix-build
+          -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/tarball/nixos-19.09
+          release.nix
+          --argstr compiler "ghc881"
+        - nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/tarball/nixos-19.09 -p cachix --run 'cachix push ihaskell result'
+        - test/acceptance.nbconvert.sh result/bin/ihaskell-nbconvert