diff --git a/plat/osx/include/build.lua b/plat/osx/include/build.lua
new file mode 100644
index 000000000..7eb73f3aa
--- /dev/null
+++ b/plat/osx/include/build.lua
@@ -0,0 +1,24 @@
+include("plat/build.lua")
+
+headermap = {}
+packagemap = {}
+
+local function addheader(h)
+	headermap[h] = "plat/osx/include/"..h
+	packagemap["$(PLATIND)/osx/include/"..h] = "plat/osx/include/"..h
+end
+
+addheader("ack/config.h")
+addheader("sys/mman.h")
+addheader("sys/types.h")
+addheader("unistd.h")
+
+acklibrary {
+	name = "headers",
+	hdrs = headermap
+}
+
+installable {
+	name = "pkg",
+	map = packagemap
+}
diff --git a/plat/osx386/build-pkg.lua b/plat/osx386/build-pkg.lua
index 8c129c8e7..6dfe1561c 100644
--- a/plat/osx386/build-pkg.lua
+++ b/plat/osx386/build-pkg.lua
@@ -17,7 +17,7 @@ installable {
 	map = {
 		"+tools",
 		"+libs",
-		"./include+pkg",
+		"plat/osx/include+pkg",
 		["$(PLATIND)/osx386/boot.o"] = "+boot",
 		["$(PLATIND)/osx386/libsys.a"] = "./libsys+lib",
 	}
diff --git a/plat/osx386/descr b/plat/osx386/descr
index f1ba978ef..e404e7a34 100644
--- a/plat/osx386/descr
+++ b/plat/osx386/descr
@@ -29,7 +29,7 @@ var EGO_PLAT_FLAGS=-M{EM}/share/ack/ego/{ARCH}.descr
 # Override the setting in fe so that files compiled for osx386 can see
 # the platform-specific headers.
 
-var C_INCLUDES=-I{PLATFORMDIR}/include -I{EM}/share/ack/include/ansi
+var C_INCLUDES=-I{EM}/share/ack/osx/include -I{EM}/share/ack/include/ansi
 
 name be
 	from .m.g
diff --git a/plat/osx386/include/build.lua b/plat/osx386/include/build.lua
index 420518f66..164e2b44a 100644
--- a/plat/osx386/include/build.lua
+++ b/plat/osx386/include/build.lua
@@ -1,24 +1,7 @@
-include("plat/build.lua")
-
-headermap = {}
-packagemap = {}
-
-local function addheader(h)
-	headermap[h] = "plat/osx/include/"..h
-	packagemap["$(PLATIND)/osx386/include/"..h] = "plat/osx/include/"..h
-end
-
-addheader("ack/config.h")
-addheader("sys/mman.h")
-addheader("sys/types.h")
-addheader("unistd.h")
-
-acklibrary {
+simplerule {
 	name = "headers",
-	hdrs = headermap
-}
-
-installable {
-	name = "pkg",
-	map = packagemap
+	deps = { "plat/osx/include+headers" },
+	ins = {},
+	outs = {},
+	commands = {},
 }
diff --git a/plat/osxppc/build-pkg.lua b/plat/osxppc/build-pkg.lua
index d6f6d5558..c94ad6ef0 100644
--- a/plat/osxppc/build-pkg.lua
+++ b/plat/osxppc/build-pkg.lua
@@ -17,7 +17,7 @@ installable {
 	map = {
 		"+tools",
 		"+libs",
-		"./include+pkg",
+		"plat/osx/include+pkg",
 		["$(PLATIND)/osxppc/boot.o"] = "+boot",
 		["$(PLATIND)/osxppc/libsys.a"] = "./libsys+lib",
 	}
diff --git a/plat/osxppc/descr b/plat/osxppc/descr
index 3ee01752d..7e8770428 100644
--- a/plat/osxppc/descr
+++ b/plat/osxppc/descr
@@ -30,7 +30,7 @@ var MACHOPT_F=-m10
 # Override the setting in fe so that files compiled for osxppc can see
 # the platform-specific headers.
 
-var C_INCLUDES=-I{PLATFORMDIR}/include -I{EM}/share/ack/include/ansi
+var C_INCLUDES=-I{EM}/share/ack/osx/include -I{EM}/share/ack/include/ansi
 
 name be
 	from .m.g
diff --git a/plat/osxppc/include/build.lua b/plat/osxppc/include/build.lua
index 375c99535..164e2b44a 100644
--- a/plat/osxppc/include/build.lua
+++ b/plat/osxppc/include/build.lua
@@ -1,24 +1,7 @@
-include("plat/build.lua")
-
-headermap = {}
-packagemap = {}
-
-local function addheader(h)
-	headermap[h] = "plat/osx/include/"..h
-	packagemap["$(PLATIND)/osxppc/include/"..h] = "plat/osx/include/"..h
-end
-
-addheader("ack/config.h")
-addheader("sys/mman.h")
-addheader("sys/types.h")
-addheader("unistd.h")
-
-acklibrary {
+simplerule {
 	name = "headers",
-	hdrs = headermap
-}
-
-installable {
-	name = "pkg",
-	map = packagemap
+	deps = { "plat/osx/include+headers" },
+	ins = {},
+	outs = {},
+	commands = {},
 }