configure - gcc >4.6 needed for JDK9 build

[David Holmes]

Hi Kim,

On 25/01/2017 7:25 AM, Kim Barrett wrote:
>> On Jan 23, 2017, at 5:34 AM, Mike Burton <mikeb at mycosystems.co.uk> wrote:
>>
>> Hello,
>>
>> I ran an OpenJDK Hack Day session on Saturday, at which some people got stuck on lost a fair bit of time, failing to build JDK9. Then we found that updating gcc from 4.6 to 4.8 fixed it.
>> Could the `configure` script be updated (by running get-source.sh) so as to check for minimum required gcc version?
>>
>> Best Regards
>>
>> Mike Burton
>
> I don’t think there is supposed to be a requirement for gcc > 4.6 in JDK 9.  I’m pretty
> sure there are folks still building with older versions.  It would be helpful to know the
> details of the platform and the error messages that led to the conclusion that something
> more recent was required.

We may have "accidentally" moved on to gcc 4.8+. Even the ppc builds, 
which are still listed as using 4.1.2 on the wiki:

https://wiki.openjdk.java.net/display/Build/Supported+Build+Platforms

are now using 4.8.5:

http://cr.openjdk.java.net/~simonis/ppc-aix-port/ (look at a build log)

So some breakage with earlier versions may have crept in. I thought I 
recalled a few issues but can't see any bug reports.

David