gcc gcov and --coverage on x86_64

[Matt Fago]

>From: Ben Elliston <bje@au1.ibm.com>
>> gcc --coverage appears to be broken on x86_64 in gcc 4.1.1 on FC6
>> (works fine with Trunk). I'm almost certain that this is a known
>> issue, but cannot find a reference in Bugzilla.
>
>I implemented that option, so can probably help you.  Contact me in
>private mail and we'll try and troubleshoot it.  If necessary, you can
>then file a bug report.

FYI, this is an issue with ccache and not gcc (I forgot about that possibility).

Guess it's time to dig into ccache.

Thanks,
Matt