--- libnatpmp-20110808/Makefile
+++ libnatpmp-20110808/Makefile
@@ -6,6 +6,7 @@
 # (c) 2007-2011 Thomas Bernard
 # http://miniupnp.free.fr/libnatpmp.html
 
+GENTOO_LIBDIR ?= lib
 OS = $(shell uname -s)
 CC ?= gcc
 INSTALL = install
@@ -36,7 +37,7 @@
 
 INSTALLPREFIX ?= $(PREFIX)/usr
 INSTALLDIRINC = $(INSTALLPREFIX)/include
-INSTALLDIRLIB = $(INSTALLPREFIX)/lib
+INSTALLDIRLIB = $(INSTALLPREFIX)/$(GENTOO_LIBDIR)
 INSTALLDIRBIN = $(INSTALLPREFIX)/bin
 
 .PHONY:	all clean depend install cleaninstall installpythonmodule