RFR: JDK-8140312: Enable new sjavac server only mode in jdk build

[Magnus Ihse Bursie]

On 2015-10-22 12:38, Erik Joelsson wrote:
> In JDK-8135131, sjavac added a thin server mode, in which only the 
> server part of sjavac is used for running plain javac. This patch adds 
> a configure option to enable this mode of running to the jdk build. 
> Later, if it seems to work well, we will consider making it default.
>
> On my workstation (linux) running the default make target went from 
> about 4m55s to 4m05s when activating this.

Did that test really use the new sjavac server? :-) The code looks 
broken, in common/autoconf/build-performance.m4 you set ENABLE_SJAVAC 
and not ENABLE_JAVAC_SERVER in the new flag.

Apart from that, it looks good. :)

/Magnus