RFR: Make Serviceability Agent attach functionality optional

[Magnus Ihse Bursie]

Hi Mikael,

Wading through my backlog here... :)

One small comment: I'd prefer if you rename the option 
"--enable-sa-attach". We try to use - as a separator between words in 
the configure arguments, instead of just mashing them together.

/Magnus

On 2017-04-13 18:19, Mikael Vidstedt wrote:
> The Serviceability Agent (aka. SA) has functionality to attach to running processes forcefully/without the cooperation of the VM, allowing “live” debugging even when the processes is stuck. On linux the implementation relies on the functionality provided by the thread_db.h header file.
>
> musl doesn’t support thread_db.h (or any other thread debugging library for that sake). This patch makes the inclusion of the attach/live debugging support optional, and only includes it if the thread_db.h header file is available.
>
> Note that the core debugging functionality still works without the attach/live debugging functionality in the SA (at least in theory, I haven’t taken core debugging for a spin yet).
>
> top: http://cr.openjdk.java.net/~mikael/webrevs/portola/sathreaddb/webrev.00/webrev/
> hotspot: http://cr.openjdk.java.net/~mikael/webrevs/portola/sathreaddb/webrev.00/hotspot/webrev/
>
> Cheers,
> Mikael
>