--- Makefile.orig	2018-04-06 10:53:30 UTC
+++ Makefile
@@ -139,7 +139,6 @@ TESTMINIWGETOBJS := $(TESTMINIWGETOBJS) 
 TESTIGDDESCPARSE := $(TESTIGDDESCPARSE) minissdpc.o
 endif
 
-LIBDIR ?= lib
 # install directories
 ifeq ($(strip $(PREFIX)),)
 INSTALLPREFIX ?= /usr
@@ -147,9 +146,9 @@ else
 INSTALLPREFIX ?= $(PREFIX)
 endif
 INSTALLDIRINC = $(INSTALLPREFIX)/include/miniupnpc
-INSTALLDIRLIB = $(INSTALLPREFIX)/$(LIBDIR)
+INSTALLDIRLIB = $(INSTALLPREFIX)/lib
 INSTALLDIRBIN = $(INSTALLPREFIX)/bin
-INSTALLDIRMAN = $(INSTALLPREFIX)/share/man
+INSTALLDIRMAN = $(INSTALLPREFIX)/man
 PKGCONFIGDIR = $(INSTALLDIRLIB)/pkgconfig
 
 FILESTOINSTALL = $(LIBRARY) $(EXECUTABLES)
@@ -229,7 +228,7 @@ distclean: clean
 
 updateversion:	miniupnpc.h
 	cp miniupnpc.h miniupnpc.h.bak
-	sed 's/\(.*MINIUPNPC_API_VERSION\s\+\)[0-9]\+/\1$(APIVERSION)/' < miniupnpc.h.bak > miniupnpc.h
+	sed -E 's/(.*MINIUPNPC_API_VERSION[[:space:]]+)[0-9]+/\1$(APIVERSION)/' < miniupnpc.h.bak > miniupnpc.h
 
 install:	updateversion $(FILESTOINSTALL)
 	$(INSTALL) -d $(DESTDIR)$(INSTALLDIRINC)