Baby steps towards building a platform --- make the assembler work.

Add ackbuilder support for C preprocessor files and yacc.

first/yacc.lua

@@ -0,0 +1,23 @@
+definerule("yacc",
+	{
+		srcs = { type="targets" },
+		commands = {
+			type="strings",
+			default={
+				"yacc -t -b %{dir}/y -d %{ins}"
+			}
+		},
+	},
+	function (e)
+		return normalrule {
+			name = e.name,
+			cwd = e.cwd,
+			ins = e.srcs,
+			outleaves = { "y.tab.c", "y.tab.h" },
+			label = e.label,
+			commands = e.commands,
+		}
+	end
+)
+
+