Windows support

.gitlab/before_script/windows/install_deps.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+
+set -eux
+
+. "$( cd "$(dirname "$0")" ; pwd -P )/../../ghcup_env"
+
+mkdir -p "${TMPDIR}" "${CABAL_DIR}"
+
+rm -rf /c/ghcup
+mkdir -p /c/ghcup
+
+CI_PROJECT_DIR=$(pwd)
+curl -o ghcup.exe https://downloads.haskell.org/~ghcup/tmp/x86_64-mingw64-ghcup-5.exe
+chmod +x ghcup.exe
+
+./ghcup.exe install ${GHC_VERSION}
+./ghcup.exe set ${GHC_VERSION}
+./ghcup.exe install-cabal ${CABAL_VERSION}
+
+rm ./ghcup.exe
+
+exit 0