diff --git a/udev/Makefile.in b/udev/Makefile.in
index 7bf184947..166a4572a 100644
--- a/udev/Makefile.in
+++ b/udev/Makefile.in
@@ -20,7 +20,7 @@ include $(top_builddir)/make.tmpl
 DM_RULES=10-dm.rules 13-dm-disk.rules 95-dm-notify.rules
 LVM_RULES=11-dm-lvm.rules 69-dm-lvm.rules
 
-DM_DIR=$(shell $(AWK) '/\#define DM_DIR/ {print $$3}' $(top_srcdir)/libdm/misc/dm-ioctl.h)
+DM_DIR=$(shell $(AWK) '/^.define DM_DIR/ {print $$3}' $(top_srcdir)/libdm/misc/dm-ioctl.h)
 
 SYSTEMDRUN=@SYSTEMD_RUN_CMD@
 ifeq ("@UDEV_RULE_EXEC_DETECTION@", "yes")