WIP adding yosys-nextpnr-xray xilinx fpga toolchain -- blinky works on arty a7 100t (except for inverted reset)

crates/fayalite/src/build/vendor/xilinx.rs

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+pub mod yosys_nextpnr_prjxray;
+
+pub(crate) fn built_in_job_kinds() -> impl IntoIterator<Item = crate::build::DynJobKind> {
+    yosys_nextpnr_prjxray::built_in_job_kinds()
+}