Clarify that README has more specific instructions than INSTALL.

Author: gwsw

Diff for: INSTALL

@@ -1,6 +1,6 @@
-   This file describes how to build and install less using 
-the "configure" script.  This only works on Unix systems.  
-To install on other systems, read the README file.
+This file contains generic instructions on how to build and
+install software using autoconf. For specific instructions
+on how to build "less", see the README or README.VER file.
 
 
 Basic Installation
@@ -24,8 +24,8 @@ diffs or instructions to the address given in the `README' so they can
 be considered for the next release.  If at some point `config.cache'
 contains results you don't want to keep, you may remove or edit it.
 
-   The file `configure.in' is used to create `configure' by a program
-called `autoconf'.  You only need `configure.in' if you want to change
+   The file `configure.ac' is used to create `configure' by a program
+called `autoconf'.  You only need `configure.ac' if you want to change
 it or regenerate `configure' using a newer version of `autoconf'.
 
 The simplest way to compile this package is: