Server expands ut8_XXX aliases to utf8mb3_XXX or utf8mb4_XXX depending
on the UTF8_IS_UTF8MB3 setting in the OLD_MODE environment variable.
Server already has the necessary code implemented in the get_utf8_flag()
method of class THD. There are several uses of this flag and all we have
to do to be in line with server is to use it.
This patch does that for DDL as work on MCOL-5705 uncovered some
problems in that area.
MCOL-2000 Process charset definitions in the ALTER TABLE .. ADD COLUMN
MCOL-2000 Yet another fixes for column charsets
* make respect for column (including table/db/server default) charsets
for the TEXT(n) fields
* round TEXT(n) column length up to the next default length of TEXT-like
subtypes, 255 (TINYTEXT), 65535 (TEXT) and so on up to 2100000000
(LONGTEXT)
