Meta: Add Serenity Kernel to gn build

Meta/gn/secondary/Kernel/generate_version_header.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+
+import subprocess
+import sys
+
+short_hash = subprocess.check_output(['git', 'rev-parse', '--short=8', 'HEAD']).decode().strip()
+if subprocess.check_output(['git', 'status', '--porcelain=v2']) and short_hash:
+    short_hash += "-modified"
+
+if not short_hash:
+    short_hash = "unknown"
+
+with open(sys.argv[1], 'w') as f:
+    f.write(fr'''/*
+ * Automatically generated by Kernel/generate_version_header.py
+ */
+
+#pragma once
+#include <AK/StringView.h>
+
+namespace Kernel {{
+
+constexpr unsigned SERENITY_MAJOR_REVISION = 1;
+constexpr unsigned SERENITY_MINOR_REVISION = 0;
+constexpr StringView SERENITY_VERSION = "{short_hash}"sv;
+
+}}
+''')