Makefile: Speedup sphinx-apidoc execution significantly
Previously the file patterns that sphinx-apidoc must exclude, stored in the APIDOC_EXCLUDES variables, were expanded by the shell before executing the tool resulting in a really long list of files to exclude. Each time a file was processed by sphinx-apidoc, its path was compared against that long list of files which was significantly slowing down the apidoc generation process.
So ensure file exclude patterns are quoted to avoid shell expansion and greatly speedup sphinx-apidoc execution.
Migrated from D8855 (view on Phabricator)