Avoid using a long-long literal for OP_INT64_MAX.

The LL suffix isn't C89, so it may not work everywhere.

src/internal.h

@@ -92,7 +92,7 @@ void op_fatal_impl(const char *_str,const char *_file,int _line);
 #  define OP_ALWAYS_TRUE(_cond) ((void)(_cond))
 # endif
 
-# define OP_INT64_MAX ((ogg_int64_t)0x7FFFFFFFFFFFFFFFLL)
+# define OP_INT64_MAX (2*(((ogg_int64_t)1<<62)-1)|1)
 # define OP_INT64_MIN (-OP_INT64_MAX-1)
 
 # define OP_MIN(_a,_b)        ((_a)<(_b)?(_a):(_b))