--- configure.ac.old	2019-12-02 20:12:56.211468994 +0000
+++ configure.ac	2019-12-02 20:13:02.041332189 +0000
@@ -74,7 +74,7 @@
   [
     AC_PATH_PROG([DOXYGEN], [doxygen])
     AS_IF([test -z "$DOXYGEN"], [AC_MSG_ERROR([doxygen not found])])
-    AC_PATH_PROG([SPHINX], [sphinx-build])
+    AC_PATH_PROG([SPHINX], [sphinx-build-3])
     AS_IF([test -z "$SPHINX"], [AC_MSG_ERROR([sphinx-build not found])])
   ]
 )