Implement `os.cpus` for Darwin (OS X) (#2115)

* adding experimental Mac implementation os os.cpus

* Simplify cpus interfaces

* remove support for osx 10

* Refactor os.cpus implementation

This commit substantially refactors how the Linux and Darwin implementations of
 `os.cpus`.  The goal is to avoid unnecessary copying and allow broader latitude
 in responding to errors per implementation.

* improved comments

* ensure no buffer overrun

* use PROCESSOR_CPU_LOAD_INFO_COUNT; not sure if this is correct

* oh teh noes

* use sliceTo instead of span

* cpu_ticks are uints

1 files changed, 1 insertions, 5 deletions

diff --git a/build.zig b/build.zig
index 33e7ad12a..fe8aa6a53 100644
--- a/build.zig
+++ b/build.zig
@@ -170,11 +170,7 @@ pub fn build(b: *Build) !void {
 
     if (std.mem.eql(u8, os_tagname, "macos")) {
         os_tagname = "darwin";
-        if (arch.isAARCH64()) {
-            target.os_version_min = std.zig.CrossTarget.OsVersion{ .semver = .{ .major = 11, .minor = 0, .patch = 0 } };
-        } else if (arch.isX86()) {
-            target.os_version_min = std.zig.CrossTarget.OsVersion{ .semver = .{ .major = 10, .minor = 14, .patch = 0 } };
-        }
+        target.os_version_min = std.zig.CrossTarget.OsVersion{ .semver = .{ .major = 11, .minor = 0, .patch = 0 } };
     } else if (target.isLinux()) {
         target.setGnuLibCVersion(2, 27, 0);
     }