Remove dependency on linux dvb headers

This fixes --disable-linuxdvb on systems without linux dvb headers
rename uuid_t to tvh_uuid_t
clock_gettime does not exist on OS X
darwin uses clang by default, enable microsoft proprietary anonimous structs
build: disable linuxdvb when compiled on OS X
save
osx: use if_nametoindex on darwin instead of SIOCGIFINDEX
save