From: Sam James <sam@gentoo.org>
Date: Fri, 10 Dec 2021 03:19:45 +0000
Subject: [PATCH 3/3] Makefile: don't override CPPFLAGS

There's no need to explicitly blank this and it prevents overrides
from the environment.

Signed-off-by: Sam James <sam@gentoo.org>
--- a/Makefile
+++ b/Makefile
@@ -26,7 +26,6 @@ CXXFILES?= iptstate.cc
 
 # THIS IS FOR NORMAL COMPILATION
 LIBS?= $(shell $(PKG_CONFIG) --libs ncurses libnetfilter_conntrack)
-CPPFLAGS=
 
 ### YOU SHOULDN'T NEED TO CHANGE ANYTHING BELOW THIS