diff --git a/libguestfs.spec b/libguestfs.spec
index 09bd2f4..343c2f8 100644
--- a/libguestfs.spec
+++ b/libguestfs.spec
@@ -457,6 +457,7 @@ if python --version && ! pkg-config python
 then
 	export PYTHON_LIBS="-lpython`python -c 'import distutils.sysconfig; print (distutils.sysconfig.get_python_version ());'`"
 	export PYTHON_CFLAGS="-I`python -c 'import distutils.sysconfig; print (distutils.sysconfig.get_python_inc ());'`"
+	export PYTHON_EXT_SUFFIX=.so
 fi
 
 #sed -i '1 s@^.*@#!/bin/sh -x@' configure