subtle: use a generic cross check instead of restricting archs

srcpkgs/subtle/template

@@ -12,6 +12,9 @@ homepage="http://subtle.subforge.org"
 conf_files="/etc/xdg/subtle/subtle.rb"
 
 if [ "$CROSS_BUILD" ]; then
+	if [ "$XBPS_WORDSIZE" != "$XBPS_TARGET_WORDSIZE" ]; then
+		broken="Word size must match"
+	fi
 	hostmakedepends+=" $makedepends"
 	CFLAGS+=" -I${XBPS_CROSS_BASE}/usr/include/ruby-2.7.0/"
 	export CFLAGS