So null merge.

        'CREATE TABLE IF NOT EXISTS ... SELECT' behaviour
BUG#55474, BUG#55499, BUG#55598, BUG#55616 and BUG#55777 are fixed
in this patch too.

This is the 5.1 part.
It implements:
- if the table exists, binlog two events: CREATE TABLE IF NOT EXISTS
  and INSERT ... SELECT

- Insert nothing and binlog nothing on master if the existing object
  is a view. It only generates a warning that table already exists.

variable assignments

The assert() that is firing is checking if expressions that can't be
null return a NULL when evaluated.
MAKEDATE() function can return NULL if the second argument is 
less then or equal to 0. Thus its nullability depends not only on 
the nullability of its arguments but also on their values.
Fixed by (overoptimistically) setting MAKEDATE() to be nullable 
despite the nullability of its arguments.
Test added.
Had to update one test result to reflect the metadata change.

The server was not checking for errors generated during
the execution of Item::val_xxx() methods when copying
data to the group, order, or distinct temp table's row.
Fixed by extending the copy_funcs() to return an error
code and by checking for that error code on the places
copy_funcs() is called. 
Test case added.

Fixing copyright text.

it couldn't parse the --ssl option.

This is a performance improvement fix.

Removed the "volatile" property of PFS_events_waits::m_wait_class.
Simplified the code accordingly.

feature

The test for bug no 50939 was put in range.test which isn't such a good idea
since it requires partitioning. Fixed by moving the test case to
partitioning_range.test.

Updated the README file.

                        
After BUG#36649, warnings for sub-statements are cleared when a 
new sub-statement is started. This is problematic since it suppresses
warnings for unsafe statements in some cases. It is important that we
always give a warning to the client, because the user needs to know
when there is a risk that the slave goes out of sync.
                        
We fixed the problem by generating warning messages for unsafe statements
while returning from a stored procedure, function, trigger or while
executing a top level statement.
                        
We also started checking unsafeness when both performance and log tables are
used. This is necessary after the performance schema which does a distinction
between performance and log tables.

Fix by adding "DEPENDS gen_lex_hash" to ADD_CUSTOM_COMMAND(),
so it regenerates lex_hash.h whenever gen_lex_lash changes.

Also, make sql dependent on GenServerSource to avoid concurrent 
generation of lex_hash.h (once for sql , and in parallel for embedded)

Post-merge fix: add missing comma.

           INSERT IGNORE ... SELECT ... UNION SELECT ...

This assert was triggered by INSERT IGNORE ... SELECT. The assert checks that a
statement either sends OK or an error to the client. If the bug was triggered
on release builds, it caused OK to be sent to the client instead of the correct
error message (in this case ER_FIELD_SPECIFIED_TWICE).

The reason the assert was triggered, was that lex->no_error was set to TRUE
during JOIN::optimize() because of IGNORE. This causes all errors to be ignored.
However, not all errors can be ignored. Some, such as ER_FIELD_SPECIFIED_TWICE
will cause the INSERT to fail no matter what. But since lex->no_error was set,
the critical errors were ignored, the INSERT failed and neither OK nor the
error message was sent to the client.

This patch fixes the problem by temporarily turning off lex->no_error in
places where errors cannot be ignored during processing of INSERT ... SELECT.

Test case added to insert.test.

Post-merge fix: remove --with-debug=full, it was only used for safemalloc.

read_rnd_buffer_size

Applied the updated description from Paul's patch.

Undo workaround as fix is being merged in