diff --git a/cpprules.in b/cpprules.in
index 2e0856bee..301305e58 100644
--- a/cpprules.in
+++ b/cpprules.in
@@ -2,8 +2,6 @@
 # Rules for generating files using the C pre-processor
 # (Replaces CppFileTarget from Imake)
 
-SED = sed
-
 SUFFIXES = .pre .man .man.pre
 
 # Translate XCOMM into pound sign with sed, rather than passing -DXCOMM=XCOMM
diff --git a/hw/dmx/Makefile.am b/hw/dmx/Makefile.am
index cdee5860a..fc9fde7b7 100644
--- a/hw/dmx/Makefile.am
+++ b/hw/dmx/Makefile.am
@@ -109,7 +109,7 @@ MAN_SUBSTS = \
 SUFFIXES = .$(APP_MAN_SUFFIX) .man
 
 .man.$(APP_MAN_SUFFIX):
-	sed $(MAN_SUBSTS) < $< > $@
+	$(SED) $(MAN_SUBSTS) < $< > $@
 
 EXTRA_DIST = $(appman_PRE)
 
diff --git a/hw/dmx/config/Makefile.am b/hw/dmx/config/Makefile.am
index 9fa7113be..7de745f53 100644
--- a/hw/dmx/config/Makefile.am
+++ b/hw/dmx/config/Makefile.am
@@ -69,7 +69,7 @@ XORGRELSTRING = @PACKAGE_STRING@
 MAN_SUBSTS = -e 's|__vendorversion__|"$(XORGRELSTRING)" "$(XORGMANNAME)"|' 
 
 .man.$(APP_MAN_SUFFIX):
-	sed $(MAN_SUBSTS) < $< > $@
+	$(SED) $(MAN_SUBSTS) < $< > $@
 
 EXTRA_DIST = \
 	$(appman_PRE) \