os/user: make user.LookupGroupId function work for large entries
The existing implementation of user.LookupGroupId function works
incorrectly with very large (>64K symbols) entries in /etc/group file.
This patch fixes this.
Fixes #43636
Change-Id: I453321f1ab15fd4d0002f97fcec7d0789e1e0da5
Reviewed-on: https://go-review.googlesource.com/c/go/+/283601
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>