Produce a basic Windows installer package

We're very early adopters of msitools' new UI feature,
so this doesn't work on MSYS2 directly yet due to an old version.

msys2-package.sh

@@ -0,0 +1,30 @@
+#!/bin/sh -e
+export LC_ALL=C.UTF-8
+cd "$MESON_BUILD_ROOT"
+
+txt2rtf() {
+	iconv -f utf-8 -t ascii//translit "$@" | awk 'BEGIN {
+		print "{\\rtf1\\ansi\\ansicpg1252\\deff0{\\fonttbl{\\f0 Tahoma;}}"
+		print "\\f0\\fs24{\\pard\\sa240"
+	} {
+		gsub(/\\/, "\\\\"); gsub(/{/, "\\{"); gsub(/}/, "\\}")
+		if (!$0) { print "\\par}{\\pard\\sa240"; prefix = "" }
+		else { print prefix $0; prefix = " " }
+	} END {
+		print "\\par}}"
+	}'
+}
+
+# We're being passed host_machine.cpu(), which will be either x86 or x86_64.
+[ "$1" = "x86" ] && arch=x86 || arch=x64
+
+wxs=fiv.wxs files=fiv-files.wxs msi=fiv.msi
+
+txt2rtf "$MESON_SOURCE_ROOT/LICENSE" > License.rtf
+find "$MESON_INSTALL_DESTDIR_PREFIX" -type f \
+	| wixl-heat --prefix "$MESON_INSTALL_DESTDIR_PREFIX/" \
+		--directory-ref INSTALLDIR --component-group CG.fiv \
+		--var var.SourceDir > "$files"
+
+wixl --verbose --arch "$arch" -D SourceDir="$MESON_INSTALL_DESTDIR_PREFIX" \
+	--ext ui --output "$msi" "$wxs" "$files"