Add initial NUMA awareness support (#378)

* Add a file containing useful macro definitions, currently a single top-level macro for obtaining the size of an array; use it to replace a sizeof(x) / sizeof(x[0]) construct in system/smbus.c . This requires switching the GCC build mode from C11 to C11 with GCC extensions.

* Initial NUMA awareness (#12) support: parse the ACPI SRAT to build up new internal structures related to proximity domains and affinity; use these structures in setup_vm_map() and calculate_chunk() to skip the work on the processors which don't belong to the proximity domain currently being tested.

Tested on a number of 1S single-domain, 2S multi-domain and 4S multi-domain platforms.

SKIP_RANGE(iterations) trick by Martin Whitaker.

boot/macros.h

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef MACROS_H
+#define MACROS_H
+/**
+ * \file
+ *
+ * Provides miscellaneous useful definitions.
+ *
+ *//*
+ * Copyright (C) 2024 Lionel Debroux.
+ */
+
+#ifndef __ASSEMBLY__
+
+#ifdef __GNUC__
+// Enhanced definitions under GCC and compatible, e.g. Clang.
+
+// These are from GPLv2 Linux 6.7, for erroring out when the argument isn't an array type.
+#define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
+#define __same_type(a, b)    __builtin_types_compatible_p(typeof(a), typeof(b))
+#define __must_be_array(a)   BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
+#define ARRAY_SIZE(arr)      (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
+#else
+// Fallback definitions.
+#define ARRAY_SIZE(var_) (sizeof(var_) / sizeof((var_)[0]))
+#endif
+
+#endif
+
+#endif