Error out if the configuration results in an empty library

This can happen for example if a dependency of 'base' (block, hash, rng)
is disabled. Noticed while testing #1034

1 files changed, 4 insertions, 1 deletions

diff --git a/configure.py b/configure.py
index ea209d7dd..f79d2a62b 100755
--- a/configure.py
+++ b/configure.py
@@ -2028,7 +2028,10 @@ class ModulesChooser(object):
             if all_modules[modname].load_on == 'vendor':
                 logging.info('Enabling use of external dependency %s' % modname)
 
-        logging.info('Loading modules: %s', ' '.join(sorted_modules_to_load))
+        if sorted_modules_to_load:
+            logging.info('Loading modules: %s', ' '.join(sorted_modules_to_load))
+        else:
+            logging.error('This configuration disables every submodule and is invalid')
 
     @staticmethod
     def _validate_state(used_modules, unused_modules):