Improve error reporting for unsupported effective_io_concurrency setting.
Give a specific error complaining about lack of posix_fadvise() when
someone tries to set effective_io_concurrency > 0 on platforms
without that.
This probably isn't worth extensive back-patching, but I (tgl) felt
cramming
Improve error reporting for unsupported effective_io_concurrency setting.
Give a specific error complaining about lack of posix_fadvise() when
someone tries to set effective_io_concurrency > 0 on platforms
without that.
This probably isn't worth extensive back-patching, but I (tgl) felt
cramming
