#503 "Mac OS X" to "macOS" naming patch

[John Brandwood]

The code in src/SDCCutil.c causes SDCC built on Mac to report itself as having been built for something like "Mac OS X x86_64".

It also reports as being build on "Mac OS X ppc" when compiled on a modern Apple Silicon (i.e. ARM64) Mac computer.

Apple changed the Mac's operating system name from "Mac OS X" to just "OS X" back in 2012 with OS X 10.8, and then changed it again to just "macOS" in 2016 with macOS 10.12.

This tiny patch just changes the name string in SDCCutil.c to catch up with Apple's now 10-year-old change in the OS name, and it also adds detection for being compiled for a modern ARM64 (aarch64) Mac.

Best wishes,

John.