diff --git a/Makefile b/Makefile
index 6d9a628..23977f2 100644
--- a/Makefile
+++ b/Makefile
@@ -3,11 +3,12 @@
 #### Start of system configuration section. ####
 
 CC = gcc
-INSTALL = /usr/bin/install
+INSTALL = /usr/bin/install -D
 INSTALL_PROGRAM = ${INSTALL}
-INSTALL_DATA = ${INSTALL} -m 644
+INSTALL_DATA = ${INSTALL} -m 755
 
-prefix = ""
+DESTDIR ?= ""
+prefix = ${DESTDIR}
 exec_prefix = ${prefix}
 
 # Where the installed binary goes.
@@ -25,7 +26,7 @@
 all:	libnss_ato libnss_ato_test 
 
 libnss_ato:	libnss_ato.c
-	${CC} -fPIC -Wall -shared -o libnss_ato.so.2 -Wl,-soname,libnss_ato.so.2 libnss_ato.c
+	${CC} ${CFLAGS} -fPIC -Wall -shared -o libnss_ato.so.2 -Wl,-soname,libnss_ato.so.2 libnss_ato.c
 
 test:	libnss_ato_test.c
 	${CC} -fPIC -Wall -o libnss_ato_test libnss_ato_test.c