with concurrent lock/unlock tables

Approved by Marko

row_create_table_for_mysql(): When the table creation fails,
free the dict_table_t object.

row_create_table_for_mysql(): When the table creation fails,
free the dict_table_t object.

No mysql-test case. Tested by creating a table, removing a *.frm file and
attempting to create the table again. Code coverage tested by
instrumentation. Tested with Valgrind.

Print an error message to stderr an get rid of the assertion.

Approved by: Jimmy Yang (over IM)

linked with foreign keys at once" from mysql-5.1-security to
mysql-5.5-security again.

rb://391 approved by Heikki

rb://477 approved by Marko

- fix ~20 warnings about redefinition of HAVE_DLOPEN 
  This was caused by new ADD_DEFINITIONS(-DHAVE_DLOPEN) inside client library CMakeLists.txt

- fix dlerror() message which ("static build?" )  which is only confusing on Windows,
  there is no "static build"

The error was introduced by typo in variable name (errormsg instead of correct
errmsg)

- Also, precache  HAVE_PEERCRED to OFF in cmake\os\WindowsCache.cmake
(to avoid useless system check).
- Also, add missing check for errors from FormatMessage().

- Also, remove annoying CMake debug printout of MALLOC_LIB if this is not set.

  connectors plugins
      
Implemented changes needed to keep the client plugin API compatible with 
the existing plugins :
      
1. Provided an options() client plugin API to let the application pass
options to the plugin after loading it
2. Added "License" (const char *) to specify the client plugin's license
3. Added "mysql_api" as a placeholder that the client library can use
to pass function pointers to the plugin so that the plugin can call the 
C lib back.
4. Updated the existing client plugins to comply with the API change.
5. Added more detailed error message generation for Windows.

Quoting from the bug report:

The pstack library has been included in MySQL since version
4.0.0. It's useless and should be removed.

Details: According to its own documentation, pstack only works
on Linux on x86 in 32 bit mode and requires LinuxThreads and a
statically linked binary. It doesn't really support any Linux
from 2003 or later and doesn't work on any other OS.