--- Makefile.stub.orig	2014-05-15 18:18:09.000000000 +0000
+++ Makefile.stub
@@ -3,8 +3,7 @@ host := $(shell gcc -dumpmachine)
 
 # Where Asis library should be installed
 # Default is into current GNAT directory
-INSTALL_DIR = $(dir $(shell which gnatls))..
-prefix=$(INSTALL_DIR)
+prefix=$(PREFIX)
 
 # Asis specific directories
 GNAT_DIR=../gnat