Use TLS variables instead of pthread specific interface

Registered by Alexey Kopytov on 2013-02-17

We should make use of the TLS mechanism provided by some compilers and platforms (notably GCC on Linux) instead of the slow pthread specific interface.

Current users of thread-local variables:
- current_thd
- my_errno
- sql_alloc
- performance schema
- threadpool

References:
- http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html#Thread_002dLocal
- https://blogs.oracle.com/seongbae/entry/pthread_get_set_specific_vs
- http://www.airs.com/blog/archives/44

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Medium
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Direction:
Needs approval
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Approved
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Unknown
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