diff --git a/build.lua b/build.lua
index 86641357d..7b28b0d30 100644
--- a/build.lua
+++ b/build.lua
@@ -6,6 +6,7 @@ installable {
 		"util/amisc+pkg",
 		"util/arch+pkg",
 		"util/misc+pkg",
+		"plat/pc86+pkg",
 	}
 }
 
diff --git a/first/ackbuilder.lua b/first/ackbuilder.lua
index 539b34897..c7184bc9f 100644
--- a/first/ackbuilder.lua
+++ b/first/ackbuilder.lua
@@ -375,6 +375,13 @@ local typeconverters = {
 		return i
 	end,
 
+	boolean = function(propname, i)
+		if (type(i) ~= "boolean") then
+			error(string.format("property '%s' must be a boolean", propname))
+		end
+		return i
+	end,
+
 	string = function(propname, i)
 		if (type(i) ~= "string") then
 			error(string.format("property '%s' must be a string", propname))
@@ -410,7 +417,7 @@ local function definerule(rulename, types, cb)
 		local args = {}
 		for propname, typespec in pairs(types) do
 			if not e[propname] then
-				if not typespec.optional and not typespec.default then
+				if not typespec.optional and (typespec.default == nil) then
 					error(string.format("missing mandatory property '%s'", propname))
 				end
 
diff --git a/first/build.lua b/first/build.lua
index dcddaae90..31c790f13 100644
--- a/first/build.lua
+++ b/first/build.lua
@@ -62,10 +62,6 @@ definerule("cfile",
 		end
 		hdrpaths = uniquify(hdrpaths)
 
-		for _, f in pairs(filenamesof(hdeps)) do
-			hsrcs[#hsrcs+1] = f
-		end
-
 		local outleaf = basename(csrcs[1]):gsub("%.c$", ".o")
 
 		return normalrule {
@@ -84,6 +80,46 @@ definerule("cfile",
 	end
 )
 
+definerule("cppfile",
+	{
+		srcs = { type="targets" },
+		deps = { type="targets", default={} },
+		outleaf = { type="string" },
+		cflags = { type="strings", default={} },
+		commands = {
+			type="strings",
+			default={
+				"$(CC) -E -P -o %{outs[1]} %{hdrpaths} %{cflags} -x c %{ins}"
+			}
+		},
+	},
+	function (e)
+		if (#e.srcs ~= 1) then
+			error("you must have exactly one input file")
+		end
+
+		local hdrpaths = {}
+		for _, t in pairs(e.deps) do
+			hdrpaths[#hdrpaths+1] = "-I"..t.dir
+		end
+		hdrpaths = uniquify(hdrpaths)
+
+		return normalrule {
+			name = e.name,
+			cwd = e.cwd,
+			ins = e.srcs,
+			deps = e.deps,
+			outleaves = {e.outleaf},
+			label = e.label,
+			commands = e.commands,
+			vars = {
+				hdrpaths = hdrpaths,
+				cflags = e.cflags,
+			}
+		}
+	end
+)
+
 definerule("bundle",
 	{
 		srcs = { type="targets" },
diff --git a/first/yacc.lua b/first/yacc.lua
new file mode 100644
index 000000000..bb308003e
--- /dev/null
+++ b/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
+)
+
+
diff --git a/mach/proto/as/build.lua b/mach/proto/as/build.lua
new file mode 100644
index 000000000..39e491813
--- /dev/null
+++ b/mach/proto/as/build.lua
@@ -0,0 +1,46 @@
+include("first/yacc.lua")
+
+definerule("build_as",
+	{
+		arch = { type="string" }
+	},
+	function(e)
+		-- Remember this is executed from the caller's directory; local
+		-- target names will resolve there
+		local archlib = clibrary {
+			name = e.name.."/archlib",
+			srcs = {},
+			hdrs = { "mach/"..e.arch.."/as/mach*.c" }
+		}
+
+		local preprocessedy = cppfile {
+			name = e.name.."/yaccinput",
+			srcs = { "mach/proto/as/comm2.y" },
+			outleaf = "comm2.y",
+			deps = {
+				"h+emheaders",
+				archlib,
+			},
+		}
+
+		local yaccfiles = yacc {
+			name = e.name.."/yacc",
+			srcs = { preprocessedy }
+		}
+
+		return cprogram {
+			name = e.name,
+			srcs = {
+				"mach/proto/as/*.c",
+				yaccfiles, -- for .c file
+			},
+			deps = {
+				"h+emheaders",
+				"modules/src/object+lib",
+				archlib,
+				yaccfiles, -- for .h file
+			}
+		}
+	end
+)
+
diff --git a/plat/build.lua b/plat/build.lua
new file mode 100644
index 000000000..e69de29bb
diff --git a/plat/pc86/build.lua b/plat/pc86/build.lua
new file mode 100644
index 000000000..c3a70093e
--- /dev/null
+++ b/plat/pc86/build.lua
@@ -0,0 +1,14 @@
+include("mach/proto/as/build.lua")
+
+build_as {
+	name = "as",
+	arch = "i86"
+}
+
+installable {
+	name = "pkg",
+	map = {
+		["$(PLATDEP)/pc86/as"] = "+as"
+	}
+}
+
diff --git a/util/misc/build.lua b/util/misc/build.lua
new file mode 100644
index 000000000..ab0a26d7d
--- /dev/null
+++ b/util/misc/build.lua
@@ -0,0 +1,82 @@
+cprogram {
+	name = "esize",
+	srcs = { "./esize.c" },
+}
+
+cprogram {
+	name = "encode",
+	srcs = { "./convert.c" },
+	deps = {
+		"h+emheaders",
+		"modules+headers",
+		"modules/src/alloc+lib",
+		"modules/src/em_code+lib_k",
+		"modules/src/print+lib",
+		"modules/src/read_em+lib_ev",
+		"modules/src/string+lib",
+		"modules/src/system+lib",
+		"util/data+em_data",
+	}
+}
+
+installable {
+	name = "pkg",
+	map = {
+		["$(PLATDEP)/em_encode"] = "+encode",
+		["$(INSDIR)/bin/esize"] = "+esize",
+		["$(PLATIND)/man/man1/esize.1"] = "./esize.1",
+		["$(PLATIND)/man/man6/em_decode.6"] = "./em_decode.6"
+	}
+}
+
+--[[
+D := util/misc
+
+define build-misc-impl
+	$(call reset)
+	$(call cfile, $D/esize.c)
+	$(call cprogram, $(BINDIR)/esize)
+	$(call installto, $(INSDIR)/bin/esize)
+
+	$(call reset)
+	$(eval q := $D/esize.1)
+	$(call installto, $(INSDIR)/share/man/man1/esize.1)
+
+	$(call reset)
+	$(eval objdir := encode)
+	$(call cfile, $D/convert.c)
+	$(eval $q: $(INCDIR)/em_comp.h $(INCDIR)/em_codeEK.h)
+	$(call rawfile, $(LIBREAD_EMEV))
+	$(call rawfile, $(LIBEMK))
+	$(call rawfile, $(LIBEM_DATA))
+	$(call rawfile, $(LIBALLOC))
+	$(call rawfile, $(LIBPRINT))
+	$(call rawfile, $(LIBSTRING))
+	$(call rawfile, $(LIBSYSTEM))
+	$(call cprogram, $(BINDIR)/em_encode)
+	$(call installto, $(PLATDEP)/em_encode)
+	$(eval EM_ENCODE := $o)
+	$(eval ACK_CORE_TOOLS += $o)
+
+	$(call reset)
+	$(eval objdir := decode)
+	$(call cfile, $D/convert.c)
+	$(eval $q: $(INCDIR)/em_comp.h $(INCDIR)/em_codeEK.h)
+	$(call rawfile, $(LIBREAD_EMKV))
+	$(call rawfile, $(LIBEME))
+	$(call rawfile, $(LIBEM_DATA))
+	$(call rawfile, $(LIBALLOC))
+	$(call rawfile, $(LIBPRINT))
+	$(call rawfile, $(LIBSTRING))
+	$(call rawfile, $(LIBSYSTEM))
+	$(call cprogram, $(BINDIR)/em_decode)
+	$(call installto, $(PLATDEP)/em_decode)
+	$(eval EM_DECODE := $o)
+
+	$(call reset)
+	$(eval q := $D/em_decode.6)
+	$(call installto, $(INSDIR)/share/man/man6/em_decode.6)
+endef
+
+$(eval $(build-misc-impl))
+--]]