Cleaner installation

Makefile

@@ -1,3 +1,7 @@
+PREFIX=/usr/local
+
+CFLAGS=-I$(PREFIX)/include
+
 EXEC = sumatra
 
 SUMATRA_SRC = sumatra.c \
@@ -22,7 +26,7 @@ all: $(EXEC)
 
 # executable compilation and link
 
-sumatra: $(SUMATRA_OBJ) $(LIBSUMA)
+sumatra: $(SUMATRA_OBJ)
 	$(CC) $(LDFLAGS) -o $@ -pthread $(SUMATRA_OBJ) $(LIBSUMAPATH) $(LIB)
 	
 ########
@@ -36,4 +40,6 @@ clean:
 	rm -f $(EXEC)
 	$(MAKE) -C ./sumalibs clean
 
-		
+install: all
+	install -d $(DESTDIR)$(PREFIX)/bin/
+	install -m 755 $(EXEC) $(DESTDIR)$(PREFIX)/bin/