fix: use per-extension subdirectory in build_temp to prevent parallel build race (#5196)#5202

bibekmhj wants to merge 1 commit intopypa:mainpypa/setuptools:mainfrom

bibekmhj:fix/parallel-build-race-condition-5196bibekmhj/setuptools:fix/parallel-build-race-condition-5196Copy head branch name to clipboard