Document build machine requirement in README

diff --git a/README b/README
index dec3f2f..84479c6 100644 (file)
--- a/README
+++ b/README
@@ -10,5 +10,9 @@ API documentation: see doc/about_docu.rst
 
 To create a source tar.gz and spec file, run
   ./make_dist.sh
-This uses python distutils with info in setup.py.
+That will try to build distributions for python 3.3 and 3.6 and will fail if
+these are not installed on the build machine. To build for a different version
+set, call
+  ./make_dist.sh VER1 VER2
+make_dist uses python distutils with info in setup.py.
 The result will be in ./dist.