ARM Macs no longer supported due to new libsimdpp dependency

[sultanqasim]

Since the last release (0.7.1), PothosCore added a dependency on libsimdpp and uses it to make architecture optimized versions of modules. Unfortunately, libsimdpp currently lacks architecture detection for for ARM Macs, and so PothosCore build fails on ARM Macs (i.e. all current Macs). Prior to the addition of the libsimdpp dependency, PothosCore could be built just fine for ARM Macs (though patch 092d120 is needed for compilation to work with recent version of libpoco).