A cleanup for MDEV-8844: Fixing compilation failure on Windows

Fixing lossy type conversions:
- from int64 to int
- from size_t to uint

sql/sql_string.cc

@@ -781,13 +781,14 @@ void Static_binary_string::qs_append(ulonglong i)
 bool Binary_string::copy_printable_hhhh(CHARSET_INFO *to_cs,
                                         CHARSET_INFO *from_cs,
                                         const char *from,
-                                        uint32 from_length)
+                                        size_t from_length)
 {
+  DBUG_ASSERT(from_length < UINT_MAX32);
   uint errors;
   uint one_escaped_char_length= MY_CS_PRINTABLE_CHAR_LENGTH * to_cs->mbminlen;
   uint one_char_length= MY_MAX(one_escaped_char_length, to_cs->mbmaxlen);
-  uint32 bytes_needed= (uint32) from_length * one_char_length;
-  if (alloc(bytes_needed))
+  ulonglong bytes_needed= from_length * one_char_length;
+  if (bytes_needed >= UINT_MAX32 || alloc((size_t) bytes_needed))
     return true;
   str_length= my_convert_using_func(Ptr, Alloced_length, to_cs,
                                     my_wc_to_printable_generic,

sql/sql_string.h

@@ -531,7 +531,7 @@ class Binary_string: public Static_binary_string
   */
   bool copy_printable_hhhh(CHARSET_INFO *to_cs,
                            CHARSET_INFO *from_cs,
-                           const char *from, uint32 from_length);
+                           const char *from, size_t from_length);
 
   bool append_ulonglong(ulonglong val);
   bool append_longlong(longlong val);

strings/ctype.c

@@ -1075,7 +1075,7 @@ my_wc_to_printable_generic(CHARSET_INFO *cs, my_wc_t wc,
     }
     str+= cs->mbminlen;
   }
-  return str - str0;
+  return (int) (str - str0);
 }