minimal gcc version for jdk/jdk and usage of -Wno-int-in-bool-context flag in HS build

[Aleksey Shipilev]

On 10/31/2018 04:40 PM, Baesken, Matthias wrote:
> https://hg.openjdk.java.net/jdk/jdk/file/896e80158d35/make/hotspot/lib/CompileJvm.gmk
> 
> DISABLED_WARNINGS_gcc := extra parentheses comment unknown-pragmas address \
>     delete-non-virtual-dtor char-subscripts array-bounds int-in-bool-context \
>     ignored-qualifiers  missing-field-initializers implicit-fallthrough \
>     empty-body strict-overflow sequence-point maybe-uninitialized \
>     misleading-indentation
> 
> 
> However   int-in-bool-context   (  -Wnoint-in-bool-context  )   seems to be available only  in gcc 7 + .
> Example call  with gcc  6  leads to a warning  :

Current jdk/jdk build works fine with 6.3.0 for me:

https://builds.shipilev.net/openjdk-jdk/openjdk-jdk-b441-20181029-jdk-12+17-linux-x86_64-fastdebug.configure.log

https://builds.shipilev.net/openjdk-jdk/openjdk-jdk-b441-20181029-jdk-12+17-linux-x86_64-fastdebug.build.log

Is this the indication that build system actually probes the warnings before trying warning options?

The troubles start when you supply additional options, apparently:
  https://bugs.openjdk.java.net/browse/JDK-8211088

-Aleksey