zig.patch

diff --git a/lib/std/zig/system.zig b/lib/std/zig/system.zig
index f6a45860b..d2155cb1e 100644
--- a/lib/std/zig/system.zig
+++ b/lib/std/zig/system.zig
@@ -259,16 +259,17 @@ pub const NativeTargetInfo = struct {
                     os.version_range.windows.min = @intToEnum(Target.Os.WindowsVersion, version);
                 },
                 .macosx => {
-                    var product_version: [32]u8 = undefined;
-                    var size: usize = product_version.len;
+                    var os_release: [32]u8 = undefined;
+                    var os_release_size: usize = os_release.len;
+
+                    // Check for High Sierra versions lower than 13.6.0.
+                    // These cannot use the osproductversion code path below since
+                    // that property is not supported in those versions.
 
-                    // The osproductversion sysctl was introduced first with
-                    // High Sierra, thankfully that's also the baseline that Zig
-                    // supports
                     std.os.sysctlbynameZ(
-                        "kern.osproductversion",
-                        &product_version,
-                        &size,
+                        "kern.osrelease",
+                        &os_release,
+                        &os_release_size,
                         null,
                         0,
                     ) catch |err| switch (err) {
@@ -276,15 +277,47 @@ pub const NativeTargetInfo = struct {
                         else => unreachable,
                     };
 
-                    const string_version = product_version[0 .. size - 1 :0];
-                    if (std.builtin.Version.parse(string_version)) |ver| {
-                        os.version_range.semver.min = ver;
-                        os.version_range.semver.max = ver;
+                    const string_release_version = os_release[0 .. os_release_size - 1 :0];
+                    var os_version: std.builtin.Version = undefined;
+                    if (std.builtin.Version.parse(string_release_version)) |ver| {
+                        // Map from the kernel version to OS version, i.e. kernel version 17.x
+                        // is equivalent to OS version 13.x, this holds for all macOS versions.
+                        os_version = std.builtin.Version {.major = ver.major - 4, .minor = ver.minor };
+                        os.version_range.semver.min = os_version;
+                        os.version_range.semver.max = os_version;
                     } else |err| switch (err) {
                         error.Overflow => {},
                         error.InvalidCharacter => {},
                         error.InvalidVersion => {},
                     }
+
+                    if (os_version.major > 13 or (os_version.major >= 13 and os_version.minor >= 6)) {
+                        // The osproductversion sysctl was introduced first with High Sierra.
+
+                        var product_version: [32]u8 = undefined;
+                        var size: usize = product_version.len;
+
+                        std.os.sysctlbynameZ(
+                            "kern.osproductversion",
+                            &product_version,
+                            &size,
+                            null,
+                            0,
+                        ) catch |err| switch (err) {
+                            error.UnknownName => unreachable,
+                            else => unreachable,
+                        };
+
+                        const string_version = product_version[0 .. size - 1 :0];
+                        if (std.builtin.Version.parse(string_version)) |ver| {
+                            os.version_range.semver.min = ver;
+                            os.version_range.semver.max = ver;
+                        } else |err| switch (err) {
+                            error.Overflow => {},
+                            error.InvalidCharacter => {},
+                            error.InvalidVersion => {},
+                        }
+                    }
                 },
                 .freebsd => {
                     // Unimplemented, fall back to default.