small corrections for C++ compliance

lobject.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lobject.c,v 2.110 2016/05/02 14:00:32 roberto Exp roberto $
+** $Id: lobject.c,v 2.111 2016/05/20 14:07:48 roberto Exp roberto $
 ** Some generic functions over Lua objects
 ** See Copyright Notice in lua.h
 */
@@ -280,7 +280,7 @@ static const char *l_str2d (const char *s, lua_Number *result) {
   endptr = l_str2dloc(s, result, mode);  /* try to convert */
   if (endptr == NULL) {  /* failed? may be a different locale */
     char buff[L_MAXLENNUM + 1];
-    char *pdot = strchr(s, '.');
+    const char *pdot = strchr(s, '.');
     if (strlen(s) > L_MAXLENNUM || pdot == NULL)
       return NULL;  /* string too long or no dot; fail */
     strcpy(buff, s);  /* copy string to buffer */

lstrlib.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lstrlib.c,v 1.250 2016/05/18 18:19:51 roberto Exp roberto $
+** $Id: lstrlib.c,v 1.251 2016/05/20 14:13:21 roberto Exp roberto $
 ** Standard library for string operations and pattern-matching
 ** See Copyright Notice in lua.h
 */
@@ -933,7 +933,7 @@ static void addquoted (luaL_Buffer *b, const char *s, size_t len) {
 static void checkdp (char *buff, int nb) {
   if (memchr(buff, '.', nb) == NULL) {  /* no dot? */
     char point = lua_getlocaledecpoint();  /* try locale point */
-    char *ppoint = memchr(buff, point, nb);
+    char *ppoint = (char *)memchr(buff, point, nb);
     if (ppoint) *ppoint = '.';  /* change it to a dot */
   }
 }