add g++ dependency
add g++ dependency

Winterflower/khmer,ged-lab/khmer,kdmurray91/khmer,F1000Research/khmer,Winterflower/khmer,souravsingh/khmer,Winterflower/khmer,souravsingh/khmer,F1000Research/khmer,ged-lab/khmer,kdmurray91/khmer,ged-lab/khmer,F1000Research/khmer,jas14/khmer,jas14/khmer,jas14/khmer,kdmurray91/khmer,souravsingh/khmer