Formatting.
diff --git a/builds/unix/configure.raw b/builds/unix/configure.raw
index 2d89c74..5ab1c6e 100644
--- a/builds/unix/configure.raw
+++ b/builds/unix/configure.raw
@@ -1193,9 +1193,9 @@ Library configuration:
# Warn if docwriter is not installed
if test $have_docwriter = no; then
- AC_MSG_NOTICE([
- Warning: \`make refdoc' will fail since pip package \`docwriter' is not
- installed. To install, run \`$PIP install docwriter', or to use a Python
+ AC_MSG_WARN([
+ \`make refdoc' will fail since pip package \`docwriter' is not installed.
+ To install, run \`$PIP install docwriter', or to use a Python
virtual environment, run \`make refdoc-venv' (requires pip package
\`virtualenv'). These operations require Python >= 3.5.
])