build: requireZig cleanup

build.zig

@@ -3,21 +3,7 @@ const builtin = @import("builtin");
 const buildpkg = @import("src/build/main.zig");
 
 comptime {
-    // This is the required Zig version for building this project. We allow
-    // any patch version but the major and minor must match exactly.
-    const required_zig = "0.13.0";
-
-    // Fail compilation if the current Zig version doesn't meet requirements.
-    const current_vsn = builtin.zig_version;
-    const required_vsn = std.SemanticVersion.parse(required_zig) catch unreachable;
-    if (current_vsn.major != required_vsn.major or
-        current_vsn.minor != required_vsn.minor)
-    {
-        @compileError(std.fmt.comptimePrint(
-            "Your Zig version v{} does not meet the required build version of v{}",
-            .{ current_vsn, required_vsn },
-        ));
-    }
+    buildpkg.requireZig("0.13.0");
 }
 
 pub fn build(b: *std.Build) !void {

src/build/main.zig

@@ -28,3 +28,6 @@ pub const XCFrameworkStep = @import("XCFrameworkStep.zig");
 pub const fish_completions = @import("fish_completions.zig").completions;
 pub const zsh_completions = @import("zsh_completions.zig").completions;
 pub const bash_completions = @import("bash_completions.zig").completions;
+
+// Helpers
+pub const requireZig = @import("zig.zig").requireZig;

src/build/zig.zig

@@ -0,0 +1,17 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+/// Require a specific version of Zig to build this project.
+pub fn requireZig(comptime required_zig: []const u8) void {
+    // Fail compilation if the current Zig version doesn't meet requirements.
+    const current_vsn = builtin.zig_version;
+    const required_vsn = std.SemanticVersion.parse(required_zig) catch unreachable;
+    if (current_vsn.major != required_vsn.major or
+        current_vsn.minor != required_vsn.minor)
+    {
+        @compileError(std.fmt.comptimePrint(
+            "Your Zig version v{} does not meet the required build version of v{}",
+            .{ current_vsn, required_vsn },
+        ));
+    }
+}