RFR: 8327621: Check return value of uname in os::get_host_name [v3]

[Johan Sjölen]

> Hi,
> 
> Trivial bug fix where we didn't check the return value of `uname(2)` on POSIX platforms. I checked callers of `get_host_name` and all wrap the calls in an `if` branch so they already handle failures.
> 
> Regards,
> Johan

Johan Sjölen has updated the pull request incrementally with two additional commits since the last revision:

 - Remove saved_errno
 - Save the errno and use

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/18157/files
  - new: https://git.openjdk.org/jdk/pull/18157/files/9094ac42..79bc8dca

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18157&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18157&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/18157.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18157/head:pull/18157

PR: https://git.openjdk.org/jdk/pull/18157