DISABLE_MYSQL_THREAD_H for strings
Also, enable unittests for perfschema

add WITH_MYSQLD_LIBS for extra linker flags for mysqld

Part V: performance schema implementation

Original revision:
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revno: 3817
revision-id: guilhem@mysql.com-20100108092756-k0zzf4kvx9b7bh38
parent: guilhem@mysql.com-20100107101133-hrrgcdqg508runuf
committer: Guilhem Bichot <guilhem@mysql.com>
branch nick: mysql-6.0-codebase-bugfixing
timestamp: Fri 2010-01-08 10:27:56 +0100
message:
  fix for BUG#50120 "Valgrind errors in any test, inside mysqltest"
  Problem was that as v->name[v->name_len] may be uninitialized (which is ok per se),
  it shouldn't be used in an if(). We remove this zero_the_char/restore_it logic by
  rather zero-terminating the v->name string when we create it in var_init().
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Original revision:

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revno: 3789.1.9
revision-id: serg@mysql.com-20091229134448-phe834ukzmi0k2e3
parent: serg@mysql.com-20091227081418-bgfg952gzumn1k3h
committer: Sergei Golubchik <serg@mysql.com>
branch nick: 6.0-codebase
timestamp: Tue 2009-12-29 14:44:48 +0100
message:
  better fix for Bug#48758 mysqltest crashes on sys_vars.collation_server_basic in gcov builds
  
  use setenv instead of putenv
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Add mysql_release.cmake intended for use by the build team (
compile options, build settings to do MySQL releases)

(handle dependent options, allow user with change WITH_READLINE to
WITH_LIBEDIT and other way around after the first compile)

Part IV: sql instrumentation

in mysqld--help test.

When mysql is compiled with different options,columns
might have different size (this depends on parameter 
names and some parameters might only be available 
when some option is switched on)

Subtraction of two unsigned months yielded a (very large) positive value.
Conversion of this to a signed value was not necessarily well defined.

Solution: do the subtraction on signed values.