[Minor] Polish alignment macros

config.h.in

 #endif
 #endif
 
+#ifndef __cplusplus
+# ifdef G_ALIGNOF
+#  define RSPAMD_ALIGNOF G_ALIGNOF
+# else
+#  define RSPAMD_ALIGNOF(t) _Alignof(t)
+# endif
+#else
+/* glib G_ALIGNOF nor C11 _Alignof are not good enough for C++, nuff said... */
+# define RSPAMD_ALIGNOF(t) alignof(t)
+#endif
+
 /* Address sanitizer */
 #ifdef __clang__
 #  if __has_feature(address_sanitizer)

src/libcryptobox/cryptobox.c

 rspamd_cryptobox_auth_ctx_len (enum rspamd_cryptobox_mode mode)
 {
 	if (G_LIKELY (mode == RSPAMD_CRYPTOBOX_MODE_25519)) {
-		return sizeof (crypto_onetimeauth_state) + _Alignof (crypto_onetimeauth_state);
+		return sizeof (crypto_onetimeauth_state) + RSPAMD_ALIGNOF(crypto_onetimeauth_state);
 	}
 	else {
 #ifndef HAVE_USABLE_OPENSSL
 rspamd_cryptobox_hash_init (rspamd_cryptobox_hash_state_t *p, const guchar *key, gsize keylen)
 {
 	crypto_generichash_blake2b_state *st = cryptobox_align_ptr (p,
-			_Alignof(crypto_generichash_blake2b_state));
+			RSPAMD_ALIGNOF(crypto_generichash_blake2b_state));
 	crypto_generichash_blake2b_init (st, key, keylen,
 			crypto_generichash_blake2b_BYTES_MAX);
 }
 rspamd_cryptobox_hash_update (rspamd_cryptobox_hash_state_t *p, const guchar *data, gsize len)
 {
 	crypto_generichash_blake2b_state *st = cryptobox_align_ptr (p,
-			_Alignof(crypto_generichash_blake2b_state));
+			RSPAMD_ALIGNOF(crypto_generichash_blake2b_state));
 	crypto_generichash_blake2b_update (st, data, len);
 }
 

src/libserver/re_cache.c

 		rspamd_regexp_set_cache_id (re, i);
 
 		if (re_class->st == NULL) {
-			(void) !posix_memalign ((void **)&re_class->st, _Alignof (rspamd_cryptobox_hash_state_t),
+			(void) !posix_memalign ((void **)&re_class->st, RSPAMD_ALIGNOF(rspamd_cryptobox_hash_state_t),
 			 		sizeof (*re_class->st));
 			g_assert (re_class->st != NULL);
 			rspamd_cryptobox_hash_init (re_class->st, NULL, 0);

src/libutil/mem_pool.h

 #define MEMPOOL_UID_LEN 20
 /* All pointers are aligned as this variable */
 #define MIN_MEM_ALIGNMENT   G_MEM_ALIGN
-#ifndef __cplusplus
-#define RSPAMD_ALIGNOF G_ALIGNOF
-#else
-#define RSPAMD_ALIGNOF(t) alignof(t)
-#endif
+
 /**
  * Destructor type definition
  */

src/libutil/multipattern.c

 	struct rspamd_multipattern *mp;
 
 	/* Align due to blake2b state */
-	(void) !posix_memalign((void **)&mp, _Alignof (struct rspamd_multipattern),
+	(void) !posix_memalign((void **)&mp, RSPAMD_ALIGNOF(struct rspamd_multipattern),
 			sizeof (*mp));
 	g_assert (mp != NULL);
 	memset (mp, 0, sizeof (*mp));
 	struct rspamd_multipattern *mp;
 
 	/* Align due to blake2b state */
-	(void) !posix_memalign((void **)&mp, _Alignof (struct rspamd_multipattern), sizeof (*mp));
+	(void) !posix_memalign((void **)&mp, RSPAMD_ALIGNOF(struct rspamd_multipattern), sizeof (*mp));
 	g_assert (mp != NULL);
 	memset (mp, 0, sizeof (*mp));
 	mp->flags = flags;

src/libutil/str_util.h

  * Check if a pointer is aligned; n must be power of two
  */
 #define rspamd_is_aligned(p, n) (((uintptr_t)(p) & ((uintptr_t)(n) - 1)) == 0)
-#define rspamd_is_aligned_as(p, v) rspamd_is_aligned(p, _Alignof(__typeof((v))))
+#define rspamd_is_aligned_as(p, v) rspamd_is_aligned(p, RSPAMD_ALIGNOF(__typeof((v))))
 gboolean rspamd_str_has_8bit (const guchar *beg, gsize len);
 
 struct UConverter;