This isn't that hard - a pipe shouldn't be needed anymore. Just require a post-2003 glibc.
So, we are desupporting the *BSDs and OS X (and Solaris etc.) now? glibc is only used on Linux and the Hurd (and debian kfreebsd, if that hasn't fallen on its face yet).
POSIX has some new spawn-type calls, btw, but I don't know how widely implemented they are or how buggy they are.
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