+Some extensions don't like parallel sphinx-build
+--- mongo-c-driver-1.16.2/build/cmake/SphinxBuild.cmake.orig 2020-02-25 06:38:41.000000000 +0100
++++ mongo-c-driver-1.16.2/build/cmake/SphinxBuild.cmake 2020-05-03 16:05:03.406177913 +0200
+@@ -40,7 +40,7 @@
+ ${CMAKE_COMMAND} -E env
+ "PYTHONDONTWRITEBYTECODE=1"
+ ${SPHINX_EXECUTABLE}
+- -j ${NPROCS} -qEW -b html
++ -qEW -b html
+ -c "${CMAKE_CURRENT_SOURCE_DIR}"
+ "${CMAKE_CURRENT_SOURCE_DIR}"
+ "${SPHINX_HTML_DIR}"
+@@ -133,7 +133,7 @@
+ ${CMAKE_COMMAND} -E env
+ "PYTHONDONTWRITEBYTECODE=1"
+ ${SPHINX_EXECUTABLE}
+- -j ${NPROCS} -qEW -b man
++ -qEW -b man
+ -c "${CMAKE_CURRENT_SOURCE_DIR}"
+ "${CMAKE_CURRENT_SOURCE_DIR}"
+ "${SPHINX_MAN_DIR}"