Update macOS name in README
The proper name for the operating system is now macOS rather
than Mac OS X. I guess it is for parity with iOS, watchOS and tvOS.
@@ -53,7 +53,7 @@ This crate provides wrappers for the following intrinsics:
- [explicit_memset():](http://netbsd.gw.com/cgi-bin/man-cgi?explicit_memset+3.i386+NetBSD-8.0)
NetBSD
- [memset_s():](https://www.unix.com/man-page/osx/3/memset_s/)
- Mac OS X/iOS, Solaris
+ macOS/iOS, Solaris
- [SecureZeroMemory():](https://msdn.microsoft.com/en-us/library/windows/desktop/aa366877(v=vs.85).aspx)
Windows
- `nightly` rust: [volatile_set_memory()] (all platforms)
