rework some (minor) things

src/atrb.h

@@ -0,0 +1,59 @@
+// Copyright (c) 2025 Quinn
+// Licensed under the MIT Licence. See LICENSE for details
+#pragma once
+
+#if defined(__GNUC__)
+#if __has_attribute(__pure__)
+#define PURE __attribute__((__pure__))
+#else
+#define PURE
+#endif
+
+#if __has_attribute(__const__)
+#define CONST __attribute__((__const__))
+#else
+#define CONST
+#endif
+
+#if __has_attribute(__noreturn__)
+#define NORET __attribute__((__noreturn__))
+#else
+#define NORET
+#endif
+
+#if __has_attribute(__malloc__)
+#define MALLOC __attribute__((__malloc__))
+#else
+#define MALLOC
+#endif
+
+#if __has_attribute(__used__)
+#define USED __attribute__((__used__))
+#else
+#define USED
+#endif
+
+#if __has_attribute(__unused__)
+#define UNUSED __attribute__((__unused__))
+#else
+#define UNUSED
+#endif
+
+#if __has_attribute(__deprecated__)
+#define DEPRECATED __attribute__((__deprecated__))
+#else
+#define DEPRECATED
+#endif
+
+#if __has_attribute(__format__)
+#define FORMAT(...) __attribute__((format(__VA_ARGS__)))
+#else
+#define FORMAT(...)
+#endif
+
+#if __has_attribute(__nonnull__)
+#define NONNULL(...) __attribute__((nonnull(__VA_ARGS__)))
+#else
+#define NONNULL(...)
+#endif
+#endif