--- docs/Makefile.orig	2021-05-20 16:12:08 UTC
+++ docs/Makefile
@@ -1,6 +1,6 @@
 # Makefile for Sphinx documentation
 SPHINXOPTS    =
-SPHINXBUILD   = sphinx-build
+SPHINXBUILD   = %%SPHINXBUILD%%
 PAPER         =
 BUILDDIR      = _build