diff --git a/modules/alloca-opt b/modules/alloca-opt
index b33522997..fe1c51e43 100644
--- a/modules/alloca-opt
+++ b/modules/alloca-opt
@@ -21,12 +21,12 @@ BUILT_SOURCES += $(ALLOCA_H)
 # doesn't have one that works with the given compiler.
 if GL_GENERATE_ALLOCA_H
 alloca.h: alloca.in.h $(top_builddir)/config.status
-	$(AM_V_GEN)rm -f $@-t $@ && \
-@NMD@	$(MKDIR_P) '%reldir%' && \
-	{ echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
-	  sed -e 's|@''HAVE_ALLOCA_H''@|$(HAVE_ALLOCA_H)|g' < $(srcdir)/alloca.in.h; \
-	} > $@-t && \
-	mv -f $@-t $@
+@NMD@	$(AM_V_at)$(MKDIR_P) '%reldir%'
+	$(AM_V_at)sed $(SED_HEADER_BEGIN) \
+           -e 's|@''HAVE_ALLOCA_H''@|$(HAVE_ALLOCA_H)|g' \
+           $(SED_HEADER_END) \
+           $(srcdir)/alloca.in.h
+	$(AM_V_AT)mv -f $@-t $@
 else
 alloca.h: $(top_builddir)/config.status
 	rm -f $@