The original backport of upstream commit aa75399b (RHEL-146564) changed
sh_iomovefd(fd) to sh_iomovefd(fd,10), pushing script-open fds into the
>=10 internal range. On c8s, sh_iomovefd uses recursive dup() rather than
fcntl(F_DUPFD, minfd). dup() always returns the lowest available fd, so
reaching >=10 requires a chain of hops (3->4->5->...->10), each sensitive
to the fd table state at that moment. If another part of ksh opens or
closes an fd between hops, the chain lands somewhere unexpected. Upstream
avoids this with fcntl(F_DUPFD, 10), which jumps directly in one syscall.
This caused fd collisions with the 3-9 user-redirect range tracked by
shp->inuse_bits, resulting in "redirection failed [Bad file descriptor]"
under complex shell environments (set -x + PS4 command substitution +
module load).
Revert the minfd argument from 10 to 3 in path.c (path_opentype, exscript)
and main.c (fdin), restoring the original fd placement behavior while
preserving the /dev/fd $0 fix from RHEL-146564.
Resolves: RHEL-188169
