Another fix to profile-build on gcc 4.6

Another fix to profile-build on gcc 4.6

Oliver reports profile builds error with new gcc 4.6, he says:

"We need to add -lgov with profile-generate AND profile-use.
So it has to be added to the second stage of building too.

The problem occurred first with the introduction of gcc4.6 and
I think this is because the previous version did find the gcov
library automatically. gcc4.6 needs more precise options and
does less guesses. I have seen it in debian, Ubuntu and also with
mingw on Windows. And all use gcc4.6."

This patch fixes the issue.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>