Use 8-byte word alignment on arm64.

The previous patch cb76b5eb used 4-byte word alignment.
Thanks to Peter Green and Hector Oron for pointing out that
8-byte alignment should be used (cf. Debian bug #757623).

include/cln/object.h

@@ -17,15 +17,15 @@ namespace cln {
 //              or immediate data.
 
 // It is possible to distinguish these because pointers are aligned.
-// cl_uint_alignment is the guaranteed alignment of a `void*' or `long'
+// cl_word_alignment is the guaranteed alignment of a `void*' or `long'
 // in memory. Must be > 1.
 #if defined(__m68k__)
   #define cl_word_alignment  2
 #endif
-#if defined(__i386__) || defined(__mips__) || defined(__mipsel__) || (defined(__sparc__) && !defined(__arch64__)) || defined(__hppa__) || defined(__arm__) || defined(__rs6000__) || defined(__m88k__) || defined(__convex__) || (defined(__s390__) && !defined(__s390x__)) || defined(__sh__) || (defined(__x86_64__) && defined(__ILP32__)) || defined(__aarch64__)
+#if defined(__i386__) || defined(__mips__) || defined(__mipsel__) || (defined(__sparc__) && !defined(__arch64__)) || defined(__hppa__) || defined(__arm__) || defined(__rs6000__) || defined(__m88k__) || defined(__convex__) || (defined(__s390__) && !defined(__s390x__)) || defined(__sh__) || (defined(__x86_64__) && defined(__ILP32__))
   #define cl_word_alignment  4
 #endif
-#if defined(__alpha__) || defined(__ia64__) || defined(__mips64__) || defined(__powerpc64__) || (defined(__sparc__) && defined(__arch64__)) || (defined(__x86_64__) && !defined(__ILP32__)) || defined(__s390x__)
+#if defined(__alpha__) || defined(__ia64__) || defined(__mips64__) || defined(__powerpc64__) || (defined(__sparc__) && defined(__arch64__)) || (defined(__x86_64__) && !defined(__ILP32__)) || defined(__s390x__) || defined(__aarch64__)
   #define cl_word_alignment  8
 #endif
 #if !defined(cl_word_alignment)