diff --git a/macros.in b/macros.in
index a08541a..1646003 100644
--- a/macros.in
+++ b/macros.in
@@ -821,6 +821,8 @@ package or when debugging this package.\
   export PKG_CONFIG_PATH\
   CONFIG_SITE=${CONFIG_SITE:-NONE}\
   export CONFIG_SITE\
+  PYTHON_DISALLOW_AMBIGUOUS_VERSION=warn\
+  export PYTHON_DISALLOW_AMBIGUOUS_VERSION\
   \
   %{verbose:set -x}%{!verbose:exec > /dev/null}\
   umask 022\