Using 'l_uint32' for unicode codepoints in scanner

'l_uint32' is enough for unicode codepoints (versus unsigned long),
and the utf-8 library already uses that type.

llex.c

@@ -359,12 +359,12 @@ static int readhexaesc (LexState *ls) {
 ** for error reporting in case of errors; 'i' counts the number of
 ** saved characters, so that they can be removed if case of success.
 */
-static unsigned long readutf8esc (LexState *ls) {
-  unsigned long r;
+static l_uint32 readutf8esc (LexState *ls) {
+  l_uint32 r;
   int i = 4;  /* number of chars to be removed: start with #"\u{X" */
   save_and_next(ls);  /* skip 'u' */
   esccheck(ls, ls->current == '{', "missing '{'");
-  r = cast_ulong(gethexa(ls));  /* must have at least one digit */
+  r = cast_uint(gethexa(ls));  /* must have at least one digit */
   while (cast_void(save_and_next(ls)), lisxdigit(ls->current)) {
     i++;
     esccheck(ls, r <= (0x7FFFFFFFu >> 4), "UTF-8 value too large");

llimits.h

@@ -138,7 +138,6 @@ typedef LUAI_UACINT l_uacInt;
 #define cast_num(i)	cast(lua_Number, (i))
 #define cast_int(i)	cast(int, (i))
 #define cast_uint(i)	cast(unsigned int, (i))
-#define cast_ulong(i)	cast(unsigned long, (i))
 #define cast_byte(i)	cast(lu_byte, (i))
 #define cast_uchar(i)	cast(unsigned char, (i))
 #define cast_char(i)	cast(char, (i))

lobject.c

@@ -382,7 +382,7 @@ size_t luaO_str2num (const char *s, TValue *o) {
 }
 
 
-int luaO_utf8esc (char *buff, unsigned long x) {
+int luaO_utf8esc (char *buff, l_uint32 x) {
   int n = 1;  /* number of bytes put in buffer (backwards) */
   lua_assert(x <= 0x7FFFFFFFu);
   if (x < 0x80)  /* ascii? */
@@ -637,7 +637,8 @@ const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
       }
       case 'U': {  /* an 'unsigned long' as a UTF-8 sequence */
         char bf[UTF8BUFFSZ];
-        int len = luaO_utf8esc(bf, va_arg(argp, unsigned long));
+        unsigned long arg = va_arg(argp, unsigned long);
+        int len = luaO_utf8esc(bf, cast(l_uint32, arg));
         addstr2buff(&buff, bf + UTF8BUFFSZ - len, cast_uint(len));
         break;
       }

lobject.h

@@ -831,7 +831,7 @@ typedef struct Table {
   if (msg == NULL) luaD_throw(L, LUA_ERRMEM);  /* only after 'va_end' */ }
 
 
-LUAI_FUNC int luaO_utf8esc (char *buff, unsigned long x);
+LUAI_FUNC int luaO_utf8esc (char *buff, l_uint32 x);
 LUAI_FUNC lu_byte luaO_ceillog2 (unsigned int x);
 LUAI_FUNC lu_byte luaO_codeparam (unsigned int p);
 LUAI_FUNC l_mem luaO_applyparam (lu_byte p, l_mem x);