https://github.com/jaymzh/iptstate/pull/21

From: Sam James <sam@gentoo.org>
Date: Fri, 10 Dec 2021 03:10:42 +0000
Subject: [PATCH 2/2] Makefile: Use pkg-config

Depending on platform, linking against ncurses may require -ltinfo as well,
and linking against netfilter_conntrack may require -lnetfilter too.

Signed-off-by: Sam James <sam@gentoo.org>
--- a/Makefile
+++ b/Makefile
@@ -25,7 +25,7 @@ CXXFLAGS?= -g -Wall -O2 -Werror=format-security -Wformat-truncation=0
 CXXFILES?= iptstate.cc
 
 # THIS IS FOR NORMAL COMPILATION
-LIBS?= -lncurses -lnetfilter_conntrack
+LIBS?= $(shell $(PKG_CONFIG) --libs ncurses libnetfilter_conntrack)
 CPPFLAGS=
 
 ### YOU SHOULDN'T NEED TO CHANGE ANYTHING BELOW THIS