Revert "sphinx: stop using parallel mode"

This reverts commit 08fd14f9589b6e0e3155ba728a5e7031b9250f91.

diff --git a/doc/Makefile b/doc/Makefile
index e08a43ecf2d6b5b0bbf5c640aecf59b6cbad23f5..9e305a8e7da557648f49f0282a93f2566a423cbc 100644 (file)
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -2,11 +2,7 @@
 #
 
 # You can set these variables from the command line.
-
-# Disable parallel reading as it can be very slow on a machine with CPUs:
-# https://github.com/sphinx-doc/sphinx/issues/10969
-
-SPHINXOPTS   ?= -q
+SPHINXOPTS   ?= -j auto -q
 SPHINXBUILD  ?= sphinx-build
 PAPER        ?=
 SOURCEDIR     = .