libGL error: unable to load driver: swrast_dri.so

[bob prohaska]

On an RPI2 www/epiphany finally compiled using portmaster. When started
it runs (somewhat)  but reports 

libGL error: unable to load driver: swrast_dri.so

Web searches suggest it's something to do with an Nvidia driver, which
seems inapplicable to an RPI2.

Is there a workaround? /usr/ports are at 441746, /usr/src is at 318674.

Thanks for reading,

bob prohaska