diff -x config.log -x config.status -ru librejs-4.9/Makefile work/librejs-4.9/Makefile
--- librejs-4.9/Makefile	2012-11-01 04:07:38.000000000 +0000
+++ librejs-4.9/Makefile	2012-11-01 10:46:44.837509858 +0000
@@ -15,7 +15,9 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see  <http://www.gnu.org/licenses/>.
 
-
+DESTDIR =
+prefix = $(DESTDIR)/usr/
+libdir = $(prefix)/lib
 
 all: 
 	cfx xpi
@@ -25,30 +27,30 @@
 doinstall: 
 	@echo "Creating Mozilla directories for system-wide add-ons and extensions";
 
-	if test ! -d "/usr/lib/mozilla"; then \
+	if test ! -d "$(libdir)/mozilla"; then \
 		echo "Creating Mozilla directory"; \
-		mkdir "/usr/lib/mozilla";\
+		install -d "$(libdir)/mozilla";\
 	fi;
 
-	if test ! -d "/usr/lib/mozilla/extensions"; then \
+	if test ! -d "$(libdir)/mozilla/extensions"; then \
 		echo "Creating extensions directory"; \
-		mkdir "/usr/lib/mozilla/extensions";\
+		install -d "$(libdir)/mozilla/extensions";\
 	fi;
 
 
-	if test ! -d "/usr/lib/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}"; then \
+	if test ! -d "$(libdir)/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}"; then \
 		echo "Creating Mozilla-browser uuid directory"; \
-		mkdir "/usr/lib/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}"; \
+		install -d "$(libdir)/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}"; \
 	fi;
 
 	@echo "Installing LibreJS";
 
-	cp librejs.xpi "/usr/lib/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}/address@hidden";
+	cp librejs.xpi "$(libdir)/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}/address@hidden";
 
 	@echo "Depending on your version of the Mozilla-browser, if LibreJS is not enabled already, you may, inside your Mozilla-browser, need to go in the menu in Tools > Add-ons and click enable where you see LibreJS.";
 
 uninstall:
-	rm "/usr/lib/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}/address@hidden";
+	rm "$(libdir)/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}/address@hidden";
 
 clean:
 	rm "librejs.xpi";