Avoid sysctl: unknown oid 'hw.optional.arm64' stderr output on Intel Macs.

Author: rami3l

rustup-init.sh

@@ -265,7 +265,8 @@ get_architecture() {
                 _cputype=x86_64
             fi
         elif [ "$_cputype" = x86_64 ]; then
-            if sysctl hw.optional.arm64 | grep -q ': 1'; then
+            # Avoid `sysctl: unknown oid 'hw.optional.arm64'` stderr output on Intel Macs.
+            if sysctl hw.optional.arm64 2> /dev/null | grep -q ': 1'; then
                 _cputype=arm64
             fi
         fi