JDK 9 RFR of JDK-8032734: Add cast lint warning to build of jdk repository

[Tim Bell]

Hi Joe:

> Work has started to clear the jdk repo of the "cast" category of lint 
> warnings (JDK-8032733, "Fix cast lint warnings in client libraries"). 
> Anticipating the time when those warnings are cleared, I'd like to now 
> get a code review of JDK-8032734 "Add cast lint warning to build of 
> jdk repository" which will enable that warning in the build:
>
> diff -r 78d907730378 make/Setup.gmk
> --- a/make/Setup.gmk    Fri Jan 24 11:03:15 2014 -0800
> +++ b/make/Setup.gmk    Fri Jan 24 13:41:24 2014 -0800
> @@ -27,7 +27,7 @@
>
>  # To build with all warnings enabled, do the following:
>  # make JAVAC_WARNINGS="-Xlint:all -Xmaxwarns 10000"
> -JAVAC_WARNINGS := 
> -Xlint:-unchecked,-deprecation,-overrides,auxiliaryclass,classfile,dep-ann,divzero,empty,overloads,static,try,varargs 
> -Werror
> +JAVAC_WARNINGS := 
> -Xlint:-unchecked,-deprecation,-overrides,auxiliaryclass,cast,classfile,dep-ann,divzero,empty,overloads,static,try,varargs 
> -Werror

Looks good to me.

Tim