M1: vendored sha2/md5 (OpenBSD 8.0) + endian/swap compat; module builds green

module/include/compat/crypto/md5.h

@@ -0,0 +1,23 @@
+/* PFLINUX compat: <crypto/md5.h> — MD5 as used by pf_ctl ruleset checksum.
+ * Implementation: compat/md5.c (vendored OpenBSD 8.0 source). */
+#ifndef _PFK_MD5_H
+#define _PFK_MD5_H
+
+#define MD5_BLOCK_LENGTH	64
+#define MD5_DIGEST_LENGTH	16
+#define MD5_DIGEST_STRING_LENGTH	(MD5_DIGEST_LENGTH * 2 + 1)
+
+typedef struct MD5Context {
+	u_int32_t state[4];
+	u_int64_t count;
+	u_int8_t buffer[MD5_BLOCK_LENGTH];
+} MD5_CTX;
+
+void MD5Init(MD5_CTX *);
+void MD5Update(MD5_CTX *, const void *, size_t);
+void MD5Final(u_int8_t[MD5_DIGEST_LENGTH], MD5_CTX *);
+void MD5Pad(MD5_CTX *);
+void MD5Transform(u_int32_t[4], const u_int8_t[MD5_BLOCK_LENGTH]);
+char *MD5End(MD5_CTX *, char *);
+
+#endif /* _PFK_MD5_H */