DRI Breakage

[vehemens]

The recent change to use a common option file for several ports including the 
dri and libGL ports results in a blank window when running glxgears on 
my -current xp system with a rv350.

I have traced the problem down to the inclusion of the following compile 
option flags to the dri port:
               -e 's|CFLAGS = |CFLAGS = ${CFLAGS} |g' \
               -e 's|OPT_FLAGS = .*|OPT_FLAGS = ${CFLAGS}|g' \

I suspect most people didn't notice as the port version wasn't bumped for this 
change.