diff --git a/Makefile.am.in b/Makefile.am.in
index d8da2c8a65554933a290a31882064bb0a0df9079..7f56d62fbb614e8e3af8c846a94fe741e7217ef4 100644
--- a/Makefile.am.in
+++ b/Makefile.am.in
@@ -30,7 +30,8 @@ libsymmetric_a_SOURCES = desCode.h desKerb.c desUtil.c desQuick.c \
 
 # Generate DES headers.
 $(des_headers): desdata
-	./desdata $@ > $@
+	./desdata $@ > $@T
+	test -s $@T && mv -f $@T $@
 
 desUtil.o: desUtil.c $(des_headers)