RFR: Fix Minimal VM build

[Aleksey Shipilev]

On 06/06/2018 11:40 AM, Andrew Haley wrote:
> On 05/07/2018 02:17 PM, Roman Kennke wrote:
>> Am 07.05.2018 um 13:46 schrieb Aleksey Shipilev:
>>> http://cr.openjdk.java.net/~shade/shenandoah/minimal-vm/webrev.01/
>>>
>>> This enables Shenandoah workspace to build cleanly with jvm-variant=minimal.
>>>
>>> Testing: hotspot_gc_shenandoah {fastdebug|release} x86_64, {server,minimal} x86 build
>>>
>>> Thanks,
>>> -Aleksey
>>>
>>
>> Ugh. All those #ifdefs ... but well ok, most of this stuff will
>> (hopefully) disappear again once we merge upstream c1 barrierset stuff.
> 
> Why not just make it an unsupported configuration?

Well, this is not Shenandoah issue, but build cleanness issue: once Shenandoah code lands in the
repo, all other build configurations should still be buildable, including minimal VM, zero, etc.

-Aleksey