--- a/docs/Makefile
+++ b/docs/Makefile
@@ -3,7 +3,7 @@
# Patching is needed here for the following reason:
# * importing the `constants` package from Kitty has a side effect that it
#   creates the user configuration directory. This package gets imported
#   while sphinx scans the code for documentation strings.
#
 
 # You can set these variables from the command line.
 SPHINXOPTS    = -j auto -T $(FAIL_WARN)
-SPHINXBUILD   = sphinx-build
+SPHINXBUILD   = PYTHONPATH=${PYTHONPATH}:.. HOME=${TMPDIR}/kitty-build-home sphinx-build
 SPHINXPROJ    = kitty
 SOURCEDIR     = .
 BUILDDIR      = _build