New apr_os_file_put flags value APR_FILE_PIPECHECK?

[William A. Rowe, Jr.]

I've noticed that we do very little to handle pipes correctly in 
apr_os_file_put().

Would it make sense to introduce APR_FILE_PIPECHECK to ask
apr_os_file_put() to first check an apr_file_info_get() of the handle, and
set the flags correctly if this is a pipe device (e.g. pass this flag for
apr_file_open_stdin/out/err when those are pipes?)
Bill