diff --git a/plat/osx386/build-tools.lua b/plat/osx386/build-tools.lua
index 097cb94d3..a1a9a8e2b 100644
--- a/plat/osx386/build-tools.lua
+++ b/plat/osx386/build-tools.lua
@@ -1,8 +1,21 @@
+include("plat/build.lua")
+
+build_as {
+	name = "as",
+	arch = "i386",
+}
+
+build_ncg {
+	name = "ncg",
+	arch = "i386",
+}
+
 return installable {
 	name = "tools",
 	map = {
+		["$(PLATDEP)/osx386/as"] = "+as",
+		["$(PLATDEP)/osx386/ncg"] = "+ncg",
 		["$(PLATIND)/descr/osx386"] = "./descr",
-		"plat/linux386+tools",
 		"plat/osx/cvmach+pkg",
 		"util/opt+pkg",
 	}
diff --git a/plat/osx386/descr b/plat/osx386/descr
index 9e4cf2577..a6f021878 100644
--- a/plat/osx386/descr
+++ b/plat/osx386/descr
@@ -34,7 +34,7 @@ var C_INCLUDES=-I{EM}/share/ack/osx/include -I{EM}/share/ack/include/ansi
 name be
 	from .m.g
 	to .s
-	program {EM}/lib/ack/linux386/ncg
+	program {EM}/lib/ack/{PLATFORM}/ncg
 	mapflag -gdb GF=-gdb
 	args {GF?} <
 	stdout
@@ -43,7 +43,7 @@ end
 name as
 	from .s.so
 	to .o
-	program {EM}/lib/ack/linux386/as
+	program {EM}/lib/ack/{PLATFORM}/as
 	args - -o > <
 	prep cond
 end
diff --git a/plat/osxppc/build-tools.lua b/plat/osxppc/build-tools.lua
index d19d25e19..eddeea85a 100644
--- a/plat/osxppc/build-tools.lua
+++ b/plat/osxppc/build-tools.lua
@@ -1,8 +1,27 @@
+include("plat/build.lua")
+
+build_as {
+	name = "as",
+	arch = "powerpc",
+}
+
+build_ncg {
+	name = "ncg",
+	arch = "powerpc",
+}
+
+build_top {
+	name = "top",
+	arch = "powerpc",
+}
+
 return installable {
 	name = "tools",
 	map = {
+		["$(PLATDEP)/osxppc/as"] = "+as",
+		["$(PLATDEP)/osxppc/ncg"] = "+ncg",
+		["$(PLATDEP)/osxppc/top"] = "+top",
 		["$(PLATIND)/descr/osxppc"] = "./descr",
-		"plat/linuxppc+tools",
 		"plat/osx/cvmach+pkg",
 		"util/opt+pkg",
 	}
diff --git a/plat/osxppc/descr b/plat/osxppc/descr
index 1aa615965..f659ff0ef 100644
--- a/plat/osxppc/descr
+++ b/plat/osxppc/descr
@@ -30,7 +30,7 @@ var C_INCLUDES=-I{EM}/share/ack/osx/include -I{EM}/share/ack/include/ansi
 name be
 	from .m.g
 	to .s
-	program {EM}/lib/ack/linuxppc/ncg
+	program {EM}/lib/ack/{PLATFORM}/ncg
 	mapflag -gdb GF=-gdb
 	args {GF?} <
 	stdout
@@ -39,7 +39,7 @@ end
 name asopt
 	from .s
 	to .so
-	program {EM}/lib/ack/linuxppc/top
+	program {EM}/lib/ack/{PLATFORM}/top
 	args
 	optimizer
 	stdin
@@ -48,7 +48,7 @@ end
 name as
 	from .s.so
 	to .o
-	program {EM}/lib/ack/linuxppc/as
+	program {EM}/lib/ack/{PLATFORM}/as
 	args - -o > <
 	prep cond
 end