configure: Enable automatic dependencies for FreeBSD make.
diff --git a/Makefile.in b/Makefile.in
index 1dd8ef1..5d9039a 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -150,6 +150,7 @@
 	@./config.status $@
 .INIT: Makefile
 .BEGIN: Makefile
+.MAKEFILEDEPS:
 
 $(RECURSE_TARGETS) $(MAKEDEP): $(ALL_MAKEFILES)