syscall: fix hang when using Unshareflags: CLONE_NEWUSER with uid/gid mapping (linux)
Note that this particular combination of properties still fails (EPERM), but it
no longer hangs.
Updates #29789
Change-Id: I29b15b85a25a7acd7ae89ffc5fed074bcdfe0a12
Reviewed-on: https://go-review.googlesource.com/c/go/+/158297
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>