Mark BROKEN

rts/lib/headlessStubs/glstub.c:232:19: error: use of undeclared identifier 'NULL'

return (GLvoid*) NULL;
                 ^

rts/lib/headlessStubs/glstub.c:236:19: error: use of undeclared identifier 'NULL'

return (GLvoid*) NULL;
                 ^

Reported by: pkg-fallout