Small changes in the header of binary files

- LUAC_VERSION is equal to LUA_VERSION_NUM, and it is stored
as an int.

- 'sizeof(int)' and 'sizeof(size_t)' removed from the header, as
the binary format does not depend on these sizes. (It uses its
own serialization for unsigned integer values.)

lundump.h

@@ -18,8 +18,7 @@
 #define LUAC_INT	0x5678
 #define LUAC_NUM	cast_num(370.5)
 
-#define MYINT(s)	(s[0]-'0')
-#define LUAC_VERSION	(MYINT(LUA_VERSION_MAJOR)*16+MYINT(LUA_VERSION_MINOR))
+#define LUAC_VERSION	LUA_VERSION_NUM
 #define LUAC_FORMAT	0	/* this is the official format */
 
 /* load one chunk; from lundump.c */