Bug#559747: zita-convolver: must not use -march=native (was FTBFS: unrecognized command line option "-march=native")

[peter green]

retitle 559747 zita-convolver: must not use -march=native
thanks

zita-convolver appears to be using -march=native , there are two 
problems with this

1: It's not supported on most debian architectures (hence a load of 
build failures)
2: Even on architectures where it is supported it's totally 
inappropriate for distribution packages since it will make packages fail 
to run on CPUs lower than the one they were built on