diff -urNp -x '*.orig' librepo-1.8.1.org/doc/python/CMakeLists.txt librepo-1.8.1/doc/python/CMakeLists.txt
--- librepo-1.8.1.org/doc/python/CMakeLists.txt	2017-09-01 17:45:17.000000000 +0200
+++ librepo-1.8.1/doc/python/CMakeLists.txt	2021-03-05 22:44:35.207770924 +0100
@@ -1,5 +1,5 @@
 ADD_CUSTOM_TARGET (doc-python
-    PYTHONPATH=${CMAKE_BINARY_DIR}/librepo/python/ sphinx-build -E -b html
+    PYTHONPATH=${CMAKE_BINARY_DIR}/librepo/python/ ${SPHINX_EXECUTABLE} -E -b html
                   ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
                   COMMENT "Building Python API documentation with Sphinx")