RFR 8241285(s): [jdk8u] fail to build hotspot with gcc-8.4.0 with or without COMPILER_WARNINGS_FATAL(Internet mail)

[linzang(臧琳)]

Dear Paul, 
    Thanks for your suggestion, it seems https://bugs.openjdk.java.net/browse/JDK-8144695 was introduced to fix this issue on jdk9, by changing "WARNINGS_AS_ERROR=" to " WARNINGS_AS_ERROR?=".
    But it is based on "--disable-warnings-as-errors" flag, and this flag set a global WARNINGS_AS_ERROR flag, which jdk8 doesn't have it, so simply backport the patch can't solve the problem. 
    I have made some change based on it . and I will mark my fix as backport.
    And I have updated the patch based on the fix of https://bugs.openjdk.java.net/browse/JDK-8144695.
    Webrev: http://cr.openjdk.java.net/~lzang/8241285/webrev01/ 
    Would you like to help review?  Thanks.
 
 
BRs,
Lin

> On 2020/3/20, 2:11 AM, "Hohensee, Paul" <hohensee at amazon.com> wrote:
>
>     Is there an existing JBS issue you can backport to get the same effect?
>     
>     Thanks,
>     Paul
>     
>     On 3/19/20, 7:00 AM, "jdk8u-dev on behalf of linzang(臧琳)" <jdk8u-dev-bounces at openjdk.java.net on behalf of linzang at tencent.com> wrote:
>         
>         Dear All,
>              Would you like to help review this tiny fix of build hotspot with gcc-8.4.0?
>              Bug: https://bugs.openjdk.java.net/browse/JDK-8241285
>              Webrev: http://cr.openjdk.java.net/~lzang/8241285/webrev/
>         
>             The fix makes gcc consider COMPILER_WARNINGS_FATAL flag, when it set to false, the warnings from gcc will not be treated as error.
>         
>         BRs,
>         Lin