Some system calls are obsolete and no longer available for EABI.
This CL replace such system call usages.

Updates golang/go#14524

Change-Id: Ib99b239455ca677e46d7097911904c45119051bd
Reviewed-on: https://go-review.googlesource.com/19945
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>