RFR (S): 8074726: Update source and target version used when compiling hotspot class files

[Staffan Larsen]

Looks good!

Thanks,
/Staffan

> On 9 mar 2015, at 20:28, Mikael Vidstedt <mikael.vidstedt at oracle.com> wrote:
> 
> 
> The Java class files under hotspot/ are currently compiled using "-source 6 -target 6" which generates unnecessarily old class files and also prints out warning messages doing so. This change does two things:
> 
> * bumps the default version used to "-source 8 -target 8"
> * uses the BOOT_JDK_SOURCETARGET from the top level build system if it has been set (typically to "-source 8 -target 8")
> 
> Tested through JPRT, the serviceability/sa regression tests as well as some Oracle internal tests.
> 
> http://cr.openjdk.java.net/~mikael/webrevs/8074726/webrev.00/webrev/
> 
> The change in make/defs.gmk is needed to pass the relevant option through to the jvmti docs compilation.
> 
> Cheers,
> Mikael
>