Support cygwin in bootstrap-haskell too

Fixes #958

scripts/bootstrap/bootstrap-haskell

@@ -35,7 +35,7 @@ export GHCUP_SKIP_UPDATE_CHECK=yes
 : "${BOOTSTRAP_HASKELL_DOWNLOADER:=curl}"
 
 case "${plat}" in
-        MSYS*|MINGW*)
+        MSYS*|MINGW*|CYGWIN*)
 			: "${GHCUP_INSTALL_BASE_PREFIX:=/c}"
 			GHCUP_DIR=$(cygpath -u "${GHCUP_INSTALL_BASE_PREFIX}/ghcup")
 			GHCUP_BIN=$(cygpath -u "${GHCUP_INSTALL_BASE_PREFIX}/ghcup/bin")
@@ -72,7 +72,7 @@ warn() {
         printf "%s\\n" "$1"
     else
         case "${plat}" in
-                MSYS*|MINGW*)
+                MSYS*|MINGW*|CYGWIN*)
                     # shellcheck disable=SC3037
                     echo -e "\\033[0;35m$1\\033[0m"
                     ;;
@@ -88,7 +88,7 @@ yellow() {
         printf "%s\\n" "$1"
     else
         case "${plat}" in
-                MSYS*|MINGW*)
+                MSYS*|MINGW*|CYGWIN*)
                     # shellcheck disable=SC3037
                     echo -e "\\033[0;33m$1\\033[0m"
                     ;;
@@ -104,7 +104,7 @@ green() {
         printf "%s\\n" "$1"
     else
         case "${plat}" in
-                MSYS*|MINGW*)
+                MSYS*|MINGW*|CYGWIN*)
                     # shellcheck disable=SC3037
                     echo -e "\\033[0;32m$1\\033[0m"
                     ;;
@@ -160,7 +160,7 @@ _done() {
 	echo
 	echo "==============================================================================="
 	case "${plat}" in
-			MSYS*|MINGW*)
+   			MSYS*|MINGW*|CYGWIN*)
 				green
 				green "All done!"
 				green
@@ -313,7 +313,7 @@ download_ghcup() {
 					;;
 			esac
 			;;
-        MSYS*|MINGW*)
+        MSYS*|MINGW*|CYGWIN*)
 			case "${arch}" in
 				x86_64|amd64)
 					_url=${GHCUP_BASE_URL}/${ghver}/x86_64-mingw64-ghcup-${ghver}.exe
@@ -326,7 +326,7 @@ download_ghcup() {
 			;;
     esac
     case "${plat}" in
-        MSYS*|MINGW*)
+        MSYS*|MINGW*|CYGWIN*)
             case "${BOOTSTRAP_HASKELL_DOWNLOADER}" in
                 "curl")
 	                # shellcheck disable=SC2086
@@ -545,7 +545,7 @@ adjust_bashrc() {
 								printf "\n%s" "[[ -f ~/.bashrc ]] && source ~/.bashrc # ghcup-env" >> "${HOME}/.bash_profile"
 							fi
 							;;
-						MSYS*|MINGW*)
+   						MSYS*|MINGW*|CYGWIN*)
 							if [ ! -e "${HOME}/.bash_profile" ] ; then
 								echo '# generated by ghcup' > "${HOME}/.bash_profile"
 								echo 'test -f ~/.profile && . ~/.profile' >> "${HOME}/.bash_profile"
@@ -595,7 +595,7 @@ adjust_cabal_config() {
 
 ask_cabal_config_init() {
 	case "${plat}" in
-			MSYS*|MINGW*)
+   			MSYS*|MINGW*|CYGWIN*)
 				if [ -n "${BOOTSTRAP_HASKELL_ADJUST_CABAL_CONFIG}" ] ; then
 					return 1
 				fi
@@ -636,7 +636,7 @@ ask_cabal_config_init() {
 
 do_cabal_config_init() {
 	case "${plat}" in
-			MSYS*|MINGW*)
+   			MSYS*|MINGW*|CYGWIN*)
 		case $1 in
 			1)
 				adjust_cabal_config
@@ -756,7 +756,7 @@ if [ -z "${GHCUP_USE_XDG_DIRS}" ] ; then
 	echo "ghcup installs only into the following directory,"
     echo "which can be removed anytime:"
 	case "${plat}" in
-			MSYS*|MINGW*)
+   			MSYS*|MINGW*|CYGWIN*)
 				echo "  $(cygpath -w "$GHCUP_DIR")"
 				;;
 			*)
@@ -823,7 +823,7 @@ if [ -z "${BOOTSTRAP_HASKELL_MINIMAL}" ] ; then
 	edo cabal update --ignore-project
 else # don't install ghc and cabal
 	case "${plat}" in
-			MSYS*|MINGW*)
+   			MSYS*|MINGW*|CYGWIN*)
 				# need to bootstrap cabal to initialize config on windows
 				# we'll remove it afterwards
 				tmp_dir="$(mktemp -d)"