$NetBSD$

Use $DESTDIR for installation.

--- Makefile.orig	2015-11-01 15:52:39.000000000 +0000
+++ Makefile
@@ -65,13 +65,13 @@ INSTALL ?=	install
 RM ?=		rm
 
 install: libraries heatshrink
-	${INSTALL} -c heatshrink ${PREFIX}/bin/
-	${INSTALL} -c libheatshrink_static.a ${PREFIX}/lib/
-	${INSTALL} -c libheatshrink_dynamic.a ${PREFIX}/lib/
-	${INSTALL} -c heatshrink_common.h ${PREFIX}/include/
-	${INSTALL} -c heatshrink_config.h ${PREFIX}/include/
-	${INSTALL} -c heatshrink_encoder.h ${PREFIX}/include/
-	${INSTALL} -c heatshrink_decoder.h ${PREFIX}/include/
+	${INSTALL} -c heatshrink ${DESTDIR}/${PREFIX}/bin/
+	${INSTALL} -c libheatshrink_static.a ${DESTDIR}/${PREFIX}/lib/
+	${INSTALL} -c libheatshrink_dynamic.a ${DESTDIR}/${PREFIX}/lib/
+	${INSTALL} -c heatshrink_common.h ${DESTDIR}/${PREFIX}/include/
+	${INSTALL} -c heatshrink_config.h ${DESTDIR}/${PREFIX}/include/
+	${INSTALL} -c heatshrink_encoder.h ${DESTDIR}/${PREFIX}/include/
+	${INSTALL} -c heatshrink_decoder.h ${DESTDIR}/${PREFIX}/include/
 
 uninstall:
 	${RM} -f ${PREFIX}/lib/libheatshrink_static.a