configure - gcc >4.6 needed for JDK9 build

[Kim Barrett]

> 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.