overriding rpmrc options inside mock

[Hans de Goede]

Hi,

I've contacted Matt Domsch to ask him to add 
-Werror-implicit-function-declaration to the default optflags with his next 
mass rebuild to get an idea of the amount of packages that this will cause to 
fail (most likely a huge amount, but we will see).

Matt is so kind as to give this a try, but, to quote him: "Where do I add that 
option to make sure it's in effect for the mock builds?"

I have no clue, so how do we this?

Regards,

Hans