Changes to enable the use of gcov

[James McKenzie]

Peter Davies wrote:
> To use gcov you must pass --coverage at both compile and link time.
> This patch means that "make CFLAGS=--coverage LDFLAGS=--coverage", "make test",
> "gcov file.c" is sufficient generate .gcov files.
>
>   
Peter:

Somehow this patch got munged in transit and will not apply to current 
git.  Can you update it and send it again?

James McKenzie