RFR (S): 8211175: Remove temporary clock initialization duplication

[David Holmes]

Thanks Robbin.

David

On 3/10/2018 1:38 AM, Robbin Ehn wrote:
> Thanks, looks good.
> 
> /Robbin
> 
> On 10/2/18 8:08 AM, David Holmes wrote:
>> webrev: http://cr.openjdk.java.net/~dholmes/8211175/webrev/
>> bug: https://bugs.openjdk.java.net/browse/JDK-8211175
>>
>> This cleans up some code duplication between os::Linux and os::Posix. 
>> os::Posix now exports the necessary clock functions so the Linux code 
>> can use those.
>>
>> Also cleaned up the clock_getres syscall as that is already provided 
>> via the direct clock_getres (no need for a syscall).
>>
>> Finally, as code in os::Linux already assumed clock_gettime etc was 
>> always available at build-time (and run-time for that matter) this is 
>> now explicitly checked via:
>>
>> + #ifndef SUPPORTS_CLOCK_MONOTONIC
>> + #error "Build platform doesn't support clock_gettime and related 
>> functionality"
>> + #endif
>>
>> Testing: tiers 1-3 (mach5)
>>
>> Thanks,
>> David