README: Indicate cython requirements
The recommended flags require cython be installed to compile
successfully. Note this in the documentation.
diff --git a/README b/README
index b977e1f..4933268 100644
--- a/README
+++ b/README
@@ -63,7 +63,8 @@
=======
Run 'bootstrap' script before configure. If you want to accept the recommended
-flags, you just need to run 'bootstrap-configure'.
+flags, you just need to run 'bootstrap-configure'. Note that the recommended
+flags require cython be installed to compile successfully.
Make sure to read the CODING-STYLE file and the other READMEs: libkmod/README
and testsuite/README.