Attempt to strengthen language in README.md

README.md

@@ -6,21 +6,16 @@ transforms (version 3.x), maintained by the FFTW authors.
 
 Unlike most other programs, most of the FFTW source code (in C) is
 generated automatically.  This repository contains the *generator* and
-it does not contain the *generated code*.  You cannot compile code
-from this repository unless you have special tools and know what you
-are doing.
+it does not contain the *generated code*.  *YOU WILL BE UNABLE TO
+COMPILE CODE FROM THIS REPOSITORY* unless you have special tools and
+know what you are doing.   In particular, do not expect things to
+work by simply executing `configure; make` or `cmake`.
 
 Most users should ignore this repository, and should instead download
 official tarballs from http://fftw.org/, which contain the generated
 code, do not require any special tools or knowledge, and can be
 compiled on any system with a C compiler.
 
-Advanced users and FFTW maintainers can obtain code from github and
-run the generation process themselves.  This is a long process that
-requires special tools.  See README for details.  (Summary: in
-addition to the usual Unix developer software, you need [GNU
-autotools](https://en.wikipedia.org/wiki/GNU_Build_System) and
-[OCaml](http://www.ocaml.org/).  Then you can run `sh mkdist.sh`
-to compile FFTW and generate `.tar.gz` files similar to the official
-releases.)
+Advanced users and FFTW maintainers may obtain code from github and
+run the generation process themselves.  See README for details.