RFR: JDK-8152959: Build crashes in jdk9-hs-comp on Linux with gnumake 3.81

[Tim Bell]

Erik:

> The VarHandles change introduced a new gensrc step that crashes when 
> using gnumake 3.81. Newer versions of make seem to handle the 
> construct in that file. I have found a way to express the makefile, 
> which is a bit more correct, and doesn't crash.
>
> The relevant part of the change is the extra dollars inside the eval. 
> An eval inside a define that is expected to be called using eval, 
> requires double escaping of dollars for correct handling. Most of the 
> time it works without though. In this case adding it seems to stop the 
> crashing.
>
> The rest of the change is minor cleanups.
>
> I intend to push this to hs-comp since that's where the varhandles 
> patch currently sits.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8152959
> Webrev: http://cr.openjdk.java.net/~erikj/8152959/webrev.jdk.01/

Looks good to me.

/Tim