RFR JDK-8196987: Resolve disabled warnings for libzip

[Alan Bateman]

On 22/05/2018 03:41, Xueming Shen wrote:
> Hi
>
> Please help review the change for JDK-8196987.
>
> issue: https://bugs.openjdk.java.net/browse/JDK-8196987
> webrev: http://cr.openjdk.java.net/~sherman/8196987/webrev
>
> It appears the change for JDK-6341887 in Deflater.c#169 "accidentally" 
> fixed the offending
> "implicit-fallthrough" warning/error [1]
>
> [1] 
> http://cr.openjdk.java.net/~sherman/6341887.David.Lloyd/webrev/src/java.base/share/native/libzip/Deflater.c.sdiff.html
>
> So the proposed change is to simply restore/enable the 
> warning_as_error. Verified with
> mach5 job.
Right, it used to have a (commented) fall through case and that has been 
removed so I think you are okay to drop that compiler option.

-Alan.