$OpenBSD: patch-src_Makefile_sub_in,v 1.1 2017/04/27 20:13:36 naddy Exp $
--- src/Makefile.sub.in.orig	Thu May  5 16:54:30 2005
+++ src/Makefile.sub.in	Thu Apr 27 22:09:46 2017
@@ -5,7 +5,8 @@ SHELL=@SHELL@
 
 CC=@CC@
 LD=@LD@
-CFLAGS=@CFLAGS@ -I..
+CFLAGS=@CFLAGS@
+CPPFLAGS=@CPPFLAGS@ -I..
 OBJEXT=@OBJEXT@
 
 SOURCES=$(shell ls -1 *.c 2>/dev/null)
@@ -33,10 +34,10 @@ endif
 
 .PHONY: depend
 depend:
-	$(CC) $(CFLAGS) -MM $(SOURCES) >.dependencies
+	$(CC) $(CPPFLAGS) -MM $(SOURCES) >.dependencies
 
 .dependencies: $(SOURCES) $(HEADERS)
-	$(CC) $(CFLAGS) -MM $(SOURCES) >$@
+	$(CC) $(CPPFLAGS) -MM $(SOURCES) >$@
 
 .PHONY: clean
 clean:
