Merge pull request #11828 from devins2518/arm-atomics

compiler_rt: aarch64 outline atomics

lib/compiler_rt.zig

@@ -1,8 +1,15 @@
+const builtin = @import("builtin");
+
 pub const panic = @import("compiler_rt/common.zig").panic;
 
 comptime {
     _ = @import("compiler_rt/atomics.zig");
 
+    // macOS has these functions inside libSystem.
+    if (builtin.cpu.arch.isAARCH64() and !builtin.os.tag.isDarwin()) {
+        _ = @import("compiler_rt/aarch64_outline_atomics.zig");
+    }
+
     _ = @import("compiler_rt/addf3.zig");
     _ = @import("compiler_rt/addhf3.zig");
     _ = @import("compiler_rt/addsf3.zig");