ref: vendor harec checker sources (#20)

ref/hare/ ships only ast/lex/parse/module/unparse — no checker. Every
bail-fix landing in A.6.2.1 (helper bail audit, N_IDENT bail audit,
enum fold) needs a `ref/harec/...` cite anchor so divergence rationale
isn't claimed against memory. PLAN.md L16, L35.

Snapshot of upstream commit ee640c6b2c17f57e8014d277a3028b262ffb7952
(`rt/+openbsd/start.ha: remove outdated comment about crt0`). 20 files:
5 src (check.c, eval.c, scope.c, types.c, type_store.c), 14 transitive
include/ headers (no parser/codegen surface), and COPYING.

License GPLv3 (COPYING included). Vendored as read-only reference per
CLAUDE.md rule 6 — no redistribution as binary, no edits.

ref/harec/include/util.h

@@ -0,0 +1,57 @@
+#ifndef HARE_UTIL_H
+#define HARE_UTIL_H
+#include <assert.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "lex.h"
+
+enum exit_status {
+	/* EXIT_SUCCESS = 0 (defined in stdlib.h) */
+	EXIT_USER = 1,
+	EXIT_LEX = 2,
+	EXIT_PARSE = 3,
+	EXIT_CHECK = 4,
+	EXIT_ABNORMAL = 255,
+};
+
+extern const char **sources;
+// Sources unaffected by the -M option
+extern const char **full_sources;
+extern size_t nsources;
+
+#define FNV1A_INIT 2166136261u
+
+uint32_t fnv1a(uint32_t hash, unsigned char c);
+uint32_t fnv1a_u32(uint32_t hash, uint32_t u32);
+uint32_t fnv1a_u64(uint32_t hash, uint64_t u64);
+uint32_t fnv1a_size(uint32_t hash, size_t sz);
+uint32_t fnv1a_s(uint32_t hash, const char *str);
+void *xcalloc(size_t n, size_t s);
+void *xrealloc(void *p, size_t s);
+char *xstrdup(const char *s);
+
+#define FORMAT(FMT_PARAM, VA_PARAM)
+#ifdef __has_attribute
+#if __has_attribute(format)
+#undef FORMAT
+#define FORMAT(FMT_PARAM, VA_PARAM) __attribute__((format(printf, FMT_PARAM, VA_PARAM)))
+#endif
+#endif
+
+int xfprintf(FILE *restrict f, const char *restrict fmt, ...) FORMAT(2, 3);
+int xvfprintf(FILE *restrict f, const char *restrict fmt, va_list ap) FORMAT(2, 0);
+
+#define malloc(a) (void *)sizeof(struct { static_assert(0, "Use xcalloc instead"); int _; })
+#define calloc(a, b) (void *)sizeof(struct { static_assert(0, "Use xcalloc instead"); int _; })
+#define realloc(a, b) (void *)sizeof(struct { static_assert(0, "Use xrealloc instead"); int _; })
+#define strdup(s) (char *)(sizeof(struct { static_assert(0, "Use xstrdup instead"); int _; })
+
+char *gen_name(int *id, const char *fmt);
+void append_buffer(char **buf, size_t *restrict ln, size_t *restrict cap,
+		const char *b, size_t sz);
+
+void errline(struct location loc);
+
+#endif