When stepping backward to end of `` expression, check for illegal chars

Bug #55546 mysqltest fails to create a new thread on HPUX
Missing call to pthread_join(), in embedded mode
This independently solves both problems, see 55426 for details.
Addendum: cannot test against a pthread_t, adds boolean flag instead

Moved an init_dynamic_string() from before to after potential die()

Added --force-restart

Allow --testcase-timeout=<mins> to be set in .opt file for test

Added code resulted in strange linking problem for embedded on Windows
Avoided by not doing this for embedded mode
It's irrelevant for embedded server anyway, --protocol will be ignored

Allow escaped quotes also in statements not starting with --
But will not support single unescaped ' or `

Follow-up patch: added test cases for -0 and while

if() treated any non-numeric string as false
Fixed to treat those as true instead
Added some test cases
Fixed missing $ in variable name in include/mix2.inc

The expect file can now include "restart:<server options>"
Also drop check-testcase if this has been done
Added comment explaining the restart: syntax

The expect file can now include "restart:<server options>"
Also drop check-testcase if this has been done

Was not covered by "skip" pattern
Replace with a more generic pattern for SUMMARY

was not complete. Bootstrap failed to pick up necessary files needed by test and hence
all tests failed.

Merge up to sunny.bains@oracle.com-20100625081841-ppulnkjk1qlazh82 .
There are 8 more changesets in mysql-5.1-innodb, but PB2 shows a
failure for a test added in one of them. If that is resolved quickly
then those 8 more changesets will be merged too.

POSIX requires that a signal handler defined with sigaction()
is not reset on delivering a signal unless SA_NODEFER or
SA_RESETHAND is set. It is therefore unnecessary to redefine
the handler on signal delivery on platforms where sigaction()
is used without those flags.

The problem is that QUICK_SELECT_DESC behaviour depends
on used_key_parts value which can be bigger than selected
best_key_parts value if an engine supports clustered key.
But used_key_parts is overwritten with best_key_parts
value that prevents from correct selection of index
access method. The fix is to preserve used_key_parts
value for further use in QUICK_SELECT_DESC.

automatic reconnect

A client with automatic reconnect enabled will see the error
message "Lost connection to MySQL server during query" if the
connection is lost between mysql_stmt_prepare() and
mysql_stmt_execute(). The mysql_stmt_errno() number, however,
is 0 -- not the corresponding value 2013.

This patch checks for the case where the prepared statement
has been pruned due to a connection loss (i.e., stmt->mysql
has been set to NULL) during a call to cli_advanced_command(),
and avoids changing the last_errno to the result of the last
reconnect attempt.

platform dependent diffs.