[Bro] Adding addition args to CFLAGS and CXXFLAGS

[Siwek, Jon]

> On Oct 28, 2014, at 2:53 PM, John Donnelly <jdonnelly at dyn.com> wrote:
> 
> This there a way I can append additional -D args to the 
> CFLAGS and CXXFLAGS when I first ./configure bro to build ?

As an example, this should prepend to the default set of flags:

	CXXFLAGS="-DMYDEFINITION" CFLAGS="-DMYDEFINITION" ./configure

- Jon