Add temporary `abc9 -nomfs` and use for `synth_xilinx -abc9`

passes/techmap/abc9.cc

diff --git a/passes/techmap/abc9.cc b/passes/techmap/abc9.cc
index 09d6e96..8932e86 100644
--- a/passes/techmap/abc9.cc
+++ b/passes/techmap/abc9.cc
@@ -247,7 +247,7 @@
 		bool cleanup, vector<int> lut_costs, bool dff_mode, std::string clk_str,
 		bool /*keepff*/, std::string delay_target, std::string /*lutin_shared*/, bool fast_mode,
 		bool show_tempdir, std::string box_file, std::string lut_file,
-		std::string wire_delay, const dict<int,IdString> &box_lookup
+		std::string wire_delay, const dict<int,IdString> &box_lookup, bool nomfs
 )
 {
 	module = current_module;
@@ -346,6 +346,11 @@
 	for (size_t pos = abc_script.find("{W}"); pos != std::string::npos; pos = abc_script.find("{W}", pos))
 		abc_script = abc_script.substr(0, pos) + wire_delay + abc_script.substr(pos+3);
 
+	if (nomfs)
+		for (size_t pos = abc_script.find("&mfs"); pos != std::string::npos; pos = abc_script.find("&mfs", pos))
+			abc_script = abc_script.erase(pos, strlen("&mfs"));
+
+
 	abc_script += stringf("; &write %s/output.aig", tempdir_name.c_str());
 	abc_script = add_echos_to_abc_cmd(abc_script);
 
@@ -921,6 +926,7 @@
 		std::string delay_target, lutin_shared = "-S 1", wire_delay;
 		bool fast_mode = false, dff_mode = false, keepff = false, cleanup = true;
 		bool show_tempdir = false;
+		bool nomfs = false;
 		vector<int> lut_costs;
 		markgroups = false;
 
@@ -1043,6 +1049,10 @@
 				wire_delay = "-W " + args[++argidx];
 				continue;
 			}
+			if (arg == "-nomfs") {
+				nomfs = true;
+				continue;
+			}
 			break;
 		}
 		extra_args(args, argidx, design);
@@ -1131,7 +1141,7 @@
 			if (!dff_mode || !clk_str.empty()) {
 				abc9_module(design, mod, script_file, exe_file, cleanup, lut_costs, dff_mode, clk_str, keepff,
 						delay_target, lutin_shared, fast_mode, show_tempdir,
-						box_file, lut_file, wire_delay, box_lookup);
+						box_file, lut_file, wire_delay, box_lookup, nomfs);
 				continue;
 			}
 
@@ -1277,7 +1287,7 @@
 				en_sig = assign_map(std::get<3>(it.first));
 				abc9_module(design, mod, script_file, exe_file, cleanup, lut_costs, !clk_sig.empty(), "$",
 						keepff, delay_target, lutin_shared, fast_mode, show_tempdir,
-						box_file, lut_file, wire_delay, box_lookup);
+						box_file, lut_file, wire_delay, box_lookup, nomfs);
 				assign_map.set(mod);
 			}
 		}

techlibs/xilinx/synth_xilinx.cc

diff --git a/techlibs/xilinx/synth_xilinx.cc b/techlibs/xilinx/synth_xilinx.cc
index 7085214..1cddd2a 100644
--- a/techlibs/xilinx/synth_xilinx.cc
+++ b/techlibs/xilinx/synth_xilinx.cc
@@ -477,10 +477,14 @@
 					log_warning("'synth_xilinx -abc9' currently supports '-family xc7' only.\n");
 				run("techmap -map +/xilinx/abc_map.v -max_iter 1");
 				run("read_verilog -icells -lib +/xilinx/abc_model.v");
+				std::string abc9_opts = " -box +/xilinx/abc_xc7.box";
+				abc9_opts += stringf(" -W %d", XC7_WIRE_DELAY);
+				abc9_opts += " -nomfs";
 				if (nowidelut)
-					run("abc9 -lut +/xilinx/abc_xc7_nowide.lut -box +/xilinx/abc_xc7.box -W " + std::to_string(XC7_WIRE_DELAY));
+					abc9_opts += " -lut +/xilinx/abc_xc7_nowide.lut";
 				else
-					run("abc9 -lut +/xilinx/abc_xc7.lut -box +/xilinx/abc_xc7.box -W " + std::to_string(XC7_WIRE_DELAY));
+					abc9_opts += " -lut +/xilinx/abc_xc7.lut";
+				run("abc9" + abc9_opts);
 			}
 			else {
 				if (nowidelut)