When using shx mkdir -p ..., occasional, unnecessarily terminal, errors can occur if the target directory is created by another process during the execution of mkdirSyncRecursive().

It's an obvious race condition that I've run into occasionally when using shx for builds with multiple parallel steps (eg, https://github.com/rivy/js.xdg-portable/runs/1896221924?check_suite_focus=true)

Ignoring 'EEXIST' errors in mkdirSyncRecursive() can mitigate this problem.