updating documentation to explain the use of CFG to
pass parameters to the configure script
diff --git a/INSTALL b/INSTALL
index 57756bd..72ded27 100644
--- a/INSTALL
+++ b/INSTALL
@@ -12,7 +12,13 @@
 
   Unix (+GNU Make):
      
+     - make  (don't worry, this will invoke a configure script)
      - make
+
+    alternatively, you can pass parameters to the configure script
+    with the CFG variable, as in:
+  
+     - make CFG="--prefix=/usr"
      - make