[PATCH v2] perf bench: Share 'start', 'end', 'runtime' global vars

[Arnaldo Carvalho de Melo]

> > Don't we have header files for that?
 
> Sure, that was the laziest/quickest way to "fix" that, the other was to
> stick a 'static' in front of it.
 
> I'll go see if pushing them to a header file will not clash with other
> stuff.

Better now? Had to prefix those, not to clash with local variables when
adding it to bench/bench.h.

Looking at the patch more can be done to share those benchmark
arguments, but this is the second minimal patch to get tools/perf to
build with the latest gcc (the one in Fedora rawhide and some other
distros).

- Arnaldo