diff --git a/python-tox.spec b/python-tox.spec
index 574e99d..725586d 100644
--- a/python-tox.spec
+++ b/python-tox.spec
@@ -16,7 +16,7 @@
 # Unset -s on python shebang - ensure that extensions installed with pip
 # to user locations are seen and properly loaded
 # Fixes https://bugzilla.redhat.com/2057015
-%global py3_shebang_flags %(echo %py3_shebang_flags | sed s/s//)
+%undefine _py3_shebang_s
 
 Name:           python-tox
 Version:        4.2.7